Dan Haren, Roy Halladay, Zack Greinke, Javier Vazquez, Kevin Slowey.
The first four pitchers on that list are aces. The fifth is Kevin Slowey.
Those five lead all qualified pitchers in strikeout-to walk ratio.
Looking at that leaderboard, Slowey sticks out. The first four pitchers have FIPs well below 3.00. Slowey's is 4.22.
Everyone's taught that to succeed as a pitcher, you have to throw quality strikes. And no pitcher in baseball understands that better than Slowey. Some (like those first four) may understand it as well as him, but none better than him.
Slowey throws the third-most strikes in baseball, and leads the majors in first-pitch strike percentage (68.5 percent).
Slowey obviously executes the "throw quality strikes" idea to perfection.
But why isn't he up with Haren, Halladay, Greinke, and Vazquez?
The first, and biggest, reason for this is Slowey's propensity to allow the home run ball. Slowey is an extreme flyball guy who works high in the strike zone. He actually has allowed as many homers as walks this year (15). He's given up more homers in his three-year career (53) than walks (50).
Slowey's high homer rate is not a fluke, as his HR/FB luck is about average. It's just that nearly half of balls hit of the Winthrop alum are outfield flies.
So that's Slowey's first problem.
Slowey's next problem is out of his control: his batting average on balls in play. Since he's a flyball guy, Slowey should actually have a BABIP around .280 or .290. However, this season, it's .352. That's why Slowey's 4.87 ERA is higher than his 4.22 FIP.
Slowey posted a pretty bad 4.90 xFIP in his 2007 debut, but improved greatly last year, with a 4.14 mark. It appeared (at least to me) that the righty was a bit of improvment away from being an ace.
This year, he's slipped backward slightly to a 4.39 xFIP, certainly not what I would have expected.
The xFIP increase has occurred, on a statistical level, because Slowey's K/BB ratio has inched down (from 5.13 to 5.00) and his FB% (and consequently, the number of homers you'd expect him to allow) has inched up (from 44.8% to 47.6%).
So those are the numbers.
But what's the real reason for Slowey's lack of improvement?
He doesn't have any good pitches.
Alright, that's a bit unfair. Slowey's fastball isn't bad. Even though it only goes 87-92 mph, averaging 88-90, he's gotten above average results from it over the course of his career, as it's been .53 runs above average per 100 pitches for his career.
However, Slowey has lost a mile per hour off his fastball this year, and he's seen his effectiveness plummet.
Year Velocity Runs Above Average/100 Pitches
2007 89.7 .64
2008 89.9 .81
2009 88.9 -.04
The fastball, Kevin Slowey's best pitch, has dropped from a plus pitch to an average pitch this season.
That's huge, because Slowey's offspeed pitches are terrible.
I've only seen Slowey pitch maybe three times, so I can't speak as well as a Twins fan can about what his offspeed stuff looks like, but he throws a slider, curveball, and changeup, and none have ever been effective in the major leagues.
The slider comes in at 1.32 runs below average per 100 pitches for Slowey's career. The curve is 1.65 below average, and the changeup is 1.85 below average.
None have ever broken out of the red for a full big-league season.
Last year, Slowey actually got OK results from his offspeed stuff, as all three pitches rated between .17 and .4 runs below average.
Given that he throws a lot of fastballs (usually near 70 percent), when Slowey has the fastball working and is coming close to average with his offspeed stuff, he's effective.
This year, however, Slowey's seen his slider slip to a run below average, his changeup slip to 1.21 below average, and his curve slip to (gulp) 3.79 below average.
It seems that Slowey had a plus fastball and functional offspeed pitches last year. This year, he has an average fastball and non-functional offspeed pitches.
Needless to say, that's not a good combination.
Still, Slowey has premium command, and he strikes out his fair share of batters. If he can get his velocity back in the 90-mph range and sharpen his breaking stuff, he could still be a #1 starter.
If he can't, he'll continue to look out of place on the walk-to-strikeout ratio leaderboard, a back-of-the-rotation guy in the company of aces.