Pitchers are fragile and should be handled with care, which is why you'll see workloads decrease in the second half and very few pitching prospects called up to the big leagues for the stretch run. That doesn't mean you should stop paying attention to what's going on down in the minors.
Here are some pitchers, two from each level, that have either been really bad or really good as of late.
LHP James Paxton, Seattle Mariners
Season stats: 4.40 ERA, 104.1 IP, 113 H, 39 BB, 104 K
While he's no Taijuan Walker (top prospect, top-of-the-rotation potential), Paxton is quietly having a solid season in Triple-A and could even get a look in the majors before season's end. The 24-year-old lefty has allowed just six earned runs over his last four starts (27 innings), including a five-hit shutout on July 8th.
A projected 2014 rotation of Felix Hernandez, Hisashi Iwakuma, Taijuan Walker and either Erasmo Ramirez, Danny Hultzen, Brandon Maurer or Paxton filling the last two spots could help elevate the M's back to the top of the division.
LHP Andy Oliver, Pittsburgh Pirates
Season stats: 3.96 ERA, 100 IP, 77 H, 91 BB, 107 K
Acquired from Detroit in the offseason, the Pirates were hoping that Oliver could decrease a walk rate the had gotten progressively worse since his first pro season in 2010. It continues to get worse (8.2 BB/9 in 2013; 6.7 BB/9 in 2012), however, and it's starting to look less likely that his major league-caliber arm will ever translate into the 25-year-old becoming a productive major league pitcher.
Oliver may have reached a low point in his season when he was removed after just 1.2 innings of his last start on July 18th after allowing eight earned runs on five hits and five walks. The Tigers had moved him to the bullpen in 2012. The Pirates could do the same before completely giving up on him.
RHP Keyvius Sampson, San Diego Padres
Season stats: 3.35 ERA, 96.2 IP, 80 H, 42 BB, 101 K (AAA/AA)
Sampson may not have been ready for Triple-A, where he struggled early in the season (8.03 ERA, 12.1 IP, 17 H, 12 BB, 7 K in four starts), but he's showing that he's more than capable of dominating at the Double-A level.
The Padres have been aggressive with the 22-year-old, jumping him a level from Low-A to Double-A in 2012, where he finished the season with a 5.00 ERA. Slowing down his ascent and allowing him to continue at the level in 2013 has been beneficial, as he's completely overmatched hitters in six of his last seven starts (four starts with zero earned runs; three starts with 10-plus strikeouts; four starts with only one or two hits allowed).
RHP Jason Adam, Kansas City Royals
Season stats: 6.14 ERA, 104 IP, 117 H, 42 BB, 91 K
He's not in the same class as Yordano Ventura and Kyle Zimmer, the Royals' top two pitching prospects, but Adam was a solid prospect who appeared to have a future in the back of a big league rotation or at least in the bullpen. His 2013 season is proving that even that projection may have been a stretch.
The 21-year-old has an ERA over 6.00 after allowing eight earned runs in 4.1 innings during his last start. He also allowed six earned runs on six hits and seven walks in his first start of the month to end a string of three consecutive quality starts.
LHP Henry Owens, Boston Red Sox
Season stats: 2.78 ERA, 97 IP, 62 H, 50 BB, 116 K
The Sox are stacked with top pitching prospects in the upper minors, including Double-A starters Matt Barnes and Anthony Ranaudo. But Henry Owens also gives the organization a potential elite prospect worth keeping an eye on down in the lower minors.
With 11 no-hit innings over his last two starts, the 6'6" lefty is doing what he can to earn a promotion to join his fellow top prospects in Double-A. His walk totals (50 BB in 97 IP) show that he still has a ways to go, but his stuff is probably too advanced for the current level and he might be ready for a new challenge before the end of the season.
RHP Parker Markel, Tampa Bay Rays
Season stats: 6.37 ERA, 82 IP, 99 H, 35 BB, 71 K
A former 39th-round pick, Markel worked his way onto the prospect radar after a solid Low-A debut in 2012 (3.53 ERA, 120 IP, 117 H, 34 BB, 96 K). His first taste of High-A ball, however, has not been so kind to the 22-year-old.
After one of his best starts of the season on June 29th (6.1 IP, 0 ER, 4 H, BB, 10 K), the 6'4" right-hander has allowed 12 earned runs in his last 10.1 innings. A move to the bullpen was a possibility for the future. That possibility could become a reality sooner than later.
RHP C.J. Edwards, Texas Rangers (traded to Cubs on 7/22)
Season stats: 1.83 ERA, 93.1 IP, 62 H, 34 BB, 122 K
If the name sounds familiar, it's because Edwards was just traded to the Cubs in the deal for Matt Garza. The names of the other players heading to Chicago—Mike Olt and Justin Grimm—are more notable because they're top prospects who have already played in the majors. But it's Edwards who could end up being the prize of the deal.
The 21-year-old, who was drafted in the 48th round by Texas in 2011, has a 1.68 ERA, 3.3 BB/9, 11.8 K/9 and only 94 hits allowed in 160.1 innings between three low minor league levels as a pro. Over his last eight starts in the Texas organization with Low-A Hickory, Edwards allowed just five earned runs in 41 innings with 15 walks and 63 strikeouts. He'll begin his Cubs career with High-A Daytona.
RHP Parker Bridwell, Baltimore Orioles
Season stats: 5.55 ERA, 95.2 IP, 95 H, 45 BB, 100 K
The No. 7-ranked prospect in the organization entering the 2011 season, according to Baseball Prospectus, Bridwell has fallen backward with his inability to succeed at the Low-A level.
With over 230 innings of experience at the level and an ERA near 6.00 over that span, the 21-year-old could be running out of time to prove he can move up the ladder in the organization. He's appeared close at times, but he cannot string together enough strong outings to think he's turned a corner.
After back-to-back brilliant starts in mid-June (14.2 IP, ER, 10 H, BB, 17 K), he allowed five earned runs in 5.2 innings in his next outing. His next start was good (5 IP, ER, 2 H, 3 BB, 7 K). And then he gave up eight earned runs in 4.2 innings his next time out. Then he was good again (6 IP, 0 ER, H, 5 BB, 6 K). Then bad again (4.2 IP, 6 ER).