Ranking MLB's Best Pitching Rotations as the Season Heats Up

Zachary D. Rymer@zachrymerMLB Lead WriterMay 16, 2018

Ranking MLB's Best Pitching Rotations as the Season Heats Up

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    Ross D. Franklin/Associated Press

    One interesting early trend of the 2018 Major League Baseball season is the comeback of starting pitchers. They've cut their ERA from 4.49 in 2017 down to 4.22.

    What better excuse to honor the best and the brightest?

    Ahead are rankings for the top 10 starting rotations in MLB at this point in the 2018 season. These are based mostly on overall quality and depth, plus style points for things that make each rotation unique.

    Another factor is health. One injury (e.g., Carlos Martinez) isn't necessarily a deal-breaker. Multiple injuries (e.g., Clayton Kershaw and Hyun-Jin Ryu) are a different story.

    Let's take it away.

         

    Note: All stats are accurate through play on Monday, May 14.

10. Arizona Diamondbacks

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    Patrick Corbin
    Patrick CorbinPatrick McDermott/Getty Images

    Top Starters

    • Patrick Corbin: 9 GS, 57.0 IP, 2.53 ERA
    • Zack Greinke: 8 GS, 48.2 IP, 3.70 ERA
    • Zack Godley: 8 GS, 46.1 IP, 4.08 ERA
    • Matt Koch: 5 GS, 33.1 IP, 2.43 ERA
    • Robbie Ray (DL): 6 GS, 27.2 IP, 4.88 ERA

           

    Key Stats: 3.69 ERA over 231.2 IP

    The Arizona Diamondbacks rotation had a depth problem coming into the season. It's only been exacerbated by Taijuan Walker's Tommy John surgery and Robbie Ray's oblique strain.

    The whole unit has avoided total ruin largely thanks to Patrick Corbin. Only four qualified starters are beating his strikeout rate of 11.8 per nine innings. He's also allowed only 14 walks and 35 hits. He's basically giving hitters nothing to work with, as his attack features a lot of sliders and few pitches in the strike zone.

    Zack Greinke has also done his part to keep Arizona's rotation afloat. He has a heck of a strikeout-to-walk ratio (8.8), and he's accomplished that despite also spending little time in the zone.

    The remainder of Arizona's rotation is getting the gist, as it's the only one in MLB with a rate of pitches in the zone under 40 percent. Hypothetically, that should be the root of a walk problem. Instead, it's mostly gotten Arizona starters a lot of whiffs and ground balls.

    Thus do D-backs starters rank 10th in MLB with a .695 OPS allowed. Depth issues be damned, they're holding strong.

9. Boston Red Sox

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    Chris Sale
    Chris SaleAssociated Press

    Top Starters

    • Chris Sale: 9 GS, 58.0 IP, 2.17 ERA
    • Rick Porcello: 9 GS, 57.2 IP, 3.28 ERA
    • David Price: 8 GS, 42.1 IP, 4.89 ERA
    • Eduardo Rodriguez: 7 GS, 37.1 IP, 4.58 ERA
    • Drew Pomeranz: 5 GS, 24.2 IP, 5.47 ERA

           

    Key Stats: 3.65 ERA over 236.2 IP

    Yes, the Boston Red Sox starting rotation has some question marks.

    Chris Sale is pretty much beyond reproach, and Rick Porcello is as solid an innings-eater as any team could ask for. But exactly what the Red Sox are going to get out of David Price is a good question every time he takes the mound, and Eduardo Rodriguez and Drew Pomeranz have yet to find their footing after beginning the season on the disabled list.

    And yet, there's room for optimism.

    For one thing, even this rotation's 3.65 ERA may not do it proper justice. Feeding into that are elite marks in innings pitched and strikeout-to-walk ratio. There's also a Statcast metric called xwOBA that claims the expected production against Boston starters is second in the American League only to that of the Houston Astros.

    A common trait among their starters is that they work the edges of the strike zone with decent success. That's a good way to keep batters on the defensive, which underscores how Red Sox starters excel at getting batters to chase outside the strike zone.

    As long as that keeps up, this Red Sox rotation should be just fine.

8. Colorado Rockies

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    Chad Bettis
    Chad BettisMatthew Stockman/Getty Images

    Top Starters

    • Chad Bettis: 8 GS, 49.0 IP, 3.12 ERA
    • Kyle Freeland: 8 GS, 47.1 IP, 3.42 ERA
    • Tyler Anderson: 9 GS, 44.0 IP, 4.30 ERA
    • Jon Gray: 9 GS, 52.0 IP, 4.85 ERA
    • German Marquez: 8 GS, 38.2 IP, 5.35 ERA

              

    Key Stats: 4.17 ERA over 231 IP

    It's hard to be impressed by the 4.17 ERA the Colorado Rockies are getting out of their starters. That only ranks 14th in MLB.

    But this is where some kind of Coors Field adjustment is necessary. A little stat called ERA- can do that, and the result is a 91 ERA- that relocates this rotation's ERA into the top 10.

    It helps that Rockies starters are mostly saying no to balls in play. Chad Bettis is only whiffing 5.5 batters per nine innings, but Jon Gray (10.2 K/9), Tyler Anderson (8.8 K/9), German Marquez (8.8 K/9) and Kyle Freeland (8.4 K/9) are on the opposite end of the spectrum.

    What also helps is how the group is also saying no to dangerous batted balls. Only Philadelphia Phillies starters are allowing a lower rate of barrels (batted balls with an ideal combination of launch angle and exit velocity) per balls in play, and only Houston Astros starters are allowing lower exit velocity on fly balls.

    The rotation's four-seam fastballs have done much of the heavy lifting in the latter regard. The best explanation for that is an age-old adage that was echoed by manager Bud Black last November: "I still think the best pitch in baseball is a well-located fastball."

7. Atlanta Braves

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    Julio Teheran
    Julio TeheranDavid Banks/Getty Images

    Top Starters

    • Julio Teheran: 9 GS, 49.0 IP, 3.49 ERA
    • Sean Newcomb: 8 GS, 46.2 IP, 2.51 ERA
    • Mike Foltynewicz: 8 GS, 42.0 IP, 3.21 ERA 
    • Brandon McCarthy: 8 GS, 40.1 IP, 5.58 ERA
    • Mike Soroka: 3 GS, 14.2 IP, 3.68 ERA

           

    Key Stats: 3.55 ERA over 215.2 IP

    If there's a bone to pick with the Atlanta Braves starting rotation, it's that the guys in it haven't had to work that hard. 

    Braves starters are averaging just 5.4 innings per start. That's below the MLB average of 5.5 innings, and it's limited their exposure to third-time-through-the-order penalty.

    Their 3.55 ERA, however, is good for sixth in MLB anyway.

    Julio Teheran, Sean Newcomb, Mike Foltynewicz and, to a lesser extent, Mike Soroka have used their good stuff to help produce a solid 8.7 K/9. It's also been difficult for batters to hit for power against Atlanta's starters. They've allowed only 68 extra-base hits.

    There's a method to that. Braves starters are among the best at pitching both right-handed batters and left-handed batters away. That makes it extraordinarily difficult for them to pull the ball, which limits access to the easiest power avenue.

    Now, if only Braves starters could eat more innings. It would sure help if they threw more strikes and lowered their rate of 3.6 walks per nine innings.

6. Philadelphia Phillies

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    Aaron Nola
    Aaron NolaAssociated Press

    Top Starters

    • Aaron Nola: 9 GS, 58.2 IP, 1.99 ERA
    • Jake Arrieta: 7 GS, 41.2 IP, 2.59 ERA
    • Nick Pivetta: 8 GS, 39.0 IP, 4.15 ERA
    • Vince Velasquez: 8 GS, 41.0 IP, 5.05 ERA
    • Ben Lively: 5 GS, 23.2 IP, 6.85 ERA

           

    Key Stats: 3.53 ERA over 216.2 IP

    To give credit where credit is due, the Philadelphia Phillies are featured here mostly because of Aaron Nola and Jake Arrieta.

    Per his 2.9 wins above replacement, the former is the most valuable pitcher in baseball right now. The latter hasn't been that good, but he's having little trouble putting a rough 2017 behind him to establish himself as one of the best free-agent signings of the past offseason.

    The Phillies rotation has otherwise been a mixed bag in terms of results. Nick Pivetta and Vince Velasquez, in particular, have struggled to find consistency.

    Even still, both Pivetta (9.7 K/9) and Velasquez (11 K/9) are at least keeping the strikeouts coming. That's their contribution to a starting rotation that's permitted just a .679 OPS, which ranks sixth in MLB.

    A more major element to that equation is how Phillies starters have not suffered hard contact. Batted balls off them have averaged just 86.9 mph (fourth in MLB). To boot, an MLB-low 3.4 percent of these balls have been barreled.

    If they can keep this up, an already good performance can get even better.

5. New York Yankees

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    Luis Severino
    Luis SeverinoAssociated Press

    Top Starters

    • Luis Severino: 9 GS, 59.0 IP, 2.14 ERA
    • CC Sabathia: 7 GS, 36.1 IP, 2.23 ERA
    • Masahiro Tanaka: 8 GS, 46.1 IP, 4.66 ERA
    • Sonny Gray: 8 GS, 38.0 IP, 6.39 ERA
    • Jordan Montgomery (DL): 6 GS, 27.1 IP, 3.62 ERA

            

    Key Stats: 3.76 ERA over 218 IP

    The New York Yankees are going to miss Jordan Montgomery as he recovers from a strained flexor tendon.

    On the bright side, Luis Severino and CC Sabathia are plenty capable of carrying the rotation.

    Severino emerged as a Cy Young Award contender in 2017, and he really hasn't changed much in 2018. His 97.6 mph heater makes him the hardest-throwing starter in MLB. Factor in his good control, sharp slider and good changeup, and he has all he needs to carry on as a No. 1.

    For his part, Sabathia is still a master of contact management. His 84.6 mph average exit velocity is the best of any American League starter.

    While they aren't sharing in Sabathia's success, Masahiro Tanaka and Sonny Gray share responsibility for how no rotation in MLB features a smaller percentage of fastballs. When taking into account that Yankees starters are the best at getting a first-pitch strike despite that, it makes a lot of sense that they're also among the best at getting hitters to chase their pitches outside the strike zone.

    This, in turn, helps explain how Yankees starters rank fourth with just a .655 OPS allowed.

4. St. Louis Cardinals

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    Dilip Vishwanat/Getty Images

    Top Starters

    • Carlos Martinez (DL): 8 GS, 50.0 IP, 1.62 ERA
    • Miles Mikolas: 7 GS, 46.2 IP, 2.51 ERA
    • Michael Wacha: 8 GS, 43.2 IP, 3.09 ERA
    • Luke Weaver: 8 GS, 40.1 IP, 4.91 ERA
    • Adam Wainwright: 4 GS, 18.0 IP, 4.00 ERA

            

    Key Stats: 3.15 ERA over 214 IP

    Carlos Martinez is going to be on the shelf for a while with a lat strain. As long as he's out, the St. Louis Cardinals rotation will be without its pace-setter.

    Although Martinez is known for his electric right arm, he's actually dialed back his fastball velocity in 2018 and become a below-average strikeout artist.

    That obviously hasn't been a kiss of death for him, though, and that has everything to do with how little hard contact he's permitted. He's getting ground balls on 52.3 percent of his balls in play and holding batters to an MLB-low 84.1 mph average exit velocity.

    As Martinez goes, so goes St. Louis' rotation. The unit leads MLB in ground-ball rate and exit velocity. That's allowing for an avoidance of home runs and extra-base hits in general, as the Cardinals boast the lowest marks in both departments.

    So, it sounds about right that they rank third in both ERA (3.15) and OPS allowed (.649).

3. Cleveland Indians

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    Corey Kluber
    Corey KluberJason Miller/Getty Images

    Top Starters

    • Corey Kluber: 9 GS, 65.1 IP, 2.34 ERA
    • Carlos Carrasco: 9 GS, 59.0 IP, 3.66 ERA
    • Mike Clevinger: 8 GS, 53.1 IP, 2.70 ERA
    • Trevor Bauer: 8 GS, 51.0 IP, 3.00 ERA
    • Josh Tomlin: 5 GS, 25.2 IP, 8.06 ERA

             

    Key Stats: 3.45 ERA over 260.2 IP

    Cleveland Indians starters are coming off a 2017 season in which they racked up more strikeouts than any rotation in history.

    They're not on pace to come close to doing that again in 2018. Their strikeout rate has fallen from 10.1 per nine innings down to just 8.3 per nine innings. That doesn't even place them within the top half of MLB.

    On one plus side, no team is allowing fewer walks per nine innings. On another, their relative dearth of strikeouts isn't due to an abundance of contact.

    Cleveland's starters still rank in the top five with their 75.5 contact percentage. They help themselves by frequently getting a first-pitch strike and by drawing a higher rate of swings outside the zone than any other rotation.

    Most of those swings come against breaking balls. And my, what breaking balls they are. Corey Kluber's slider is the best of the bunch, but neither Carlos Carrasco's slider, Trevor Bauer's curveball nor Mike Clevinger's slider is a slouch.

    If one substituted Adam Plutko for Josh Tomlin, Cleveland's rotation would have a 2.94 ERA and 13 fewer home runs allowed.

2. Washington Nationals

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    Max Scherzer
    Max ScherzerMitchell Layton/Getty Images

    Top Starters

    • Max Scherzer: 9 GS, 58.2 IP, 1.69 ERA
    • Stephen Strasburg: 9 GS, 60.1 IP, 3.28 ERA
    • Gio Gonzalez: 8 GS, 44.2 IP, 2.22 ERA
    • Tanner Roark: 8 GS, 51.1 IP, 3.33 ERA
    • Jeremy Hellickson: 6 GS, 32.2 IP, 2.20 ERA

            

    Key Stats: 2.91 ERA over 256.2 IP

    The Washington Nationals rotation might have made the cut for this list even if it were Max Scherzer and four Little Leaguers.

    Already with three Cy Young Awards, Scherzer is well on his way to a fourth mainly because he's not allowing anyone to put the ball in play against him. He's whiffed 91 batters in his 58.2 innings. That comes out to 14 strikeouts per nine innings, which is on track to set a single-season record.

    Oh, and Scherzer has also walked only 13 batters all season. As Nats closer Sean Doolittle said"He is just in attack mode all the time."

    Meanwhile, it's certainly not four Little Leaguers who are following Scherzer in Washington's rotation. Stephen Strasburg, Gio Gonzalez and Tanner Roark are living up to lofty expectations, and Jeremy Hellickson is finding redemption after a fall from grace in 2017.

    The whole ensemble is a fascinating blend of excellent stuff and pitching smarts. Among the rewards are NL-best marks in inningsK/9, BB/9OPS allowed and, naturally, ERA.

1. Houston Astros

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    Gerrit Cole
    Gerrit ColeEzra Shaw/Getty Images

    Top Starters

    • Justin Verlander: 9 GS, 59.2 IP, 1.21 ERA
    • Gerrit Cole: 8 GS, 56.2 IP, 1.43 ERA
    • Charlie Morton: 8 GS, 48.2 IP, 2.03 ERA
    • Dallas Keuchel: 9 GS, 58.0 IP, 3.10 ERA
    • Lance McCullers Jr.: 9 GS, 52.0 IP, 3.63 ERA

            

    Key Stats: 2.26 ERA over 275.0 IP

    Anyone who's surprised at this should really be paying more attention to the Houston Astros.

    It should be an exaggeration to say their starting rotation leads MLB in everything, but that's the case for the most part. Innings. ERA. Strikeouts per nine. OPS allowed

    And it's been a true group effort.

    Justin Verlander is down to a 1.15 ERA in 14 regular-season starts as an Astro. The move to Houston has had a similar effect on Gerrit Cole, who's nearly matching Max Scherzer's K/9 pace—and Cole is actually leading in strikeouts per batters faced. Charlie Morton is making the most of his own excellent stuff, and Dallas Keuchel and Lance McCullers Jr. would be aces on virtually any other staff.

    What separates this staff from others? Part of it is velocity. Part of it is spin. But perhaps the biggest part of it is sheer determination.

    "There's a team within a team there, especially with the starting rotation," Astros manager AJ Hinch said. "They want to one-up each other. They want to dominate like the guy before them did."

    Well, it's working.

        

    Stats courtesy of Baseball Reference, FanGraphs and Baseball Savant.