With the first days of spring training drawing near, I want to move back into doing some analytical posts since I’ve gotten away from them over this long winter. Since I promised a Kevin Correia post shortly after his signing and never got around to doing it, I think he’s a good place to start.
There are plenty of reasons to think that Correia may have been a poor signing for the Pirates. He’s officially on the wrong side of 30 and he’s coming off of a bad season in a good pitcher’s park. He gave up a bunch of homers in Petco last year, which could translate into a ton of bombs in PNC this year. Prior to his time in San Diego, he struggled quite a bit with San Francisco, who also plays in a pitcher-friendly environment. He’s never topped 200 innings. These are all valid concerns, but I feel like he at least warrants a bit of a closer look. He’s had some recent success, after all, and he’s not really all that far removed from it.
Correia’s not a big strikeout pitcher (career rate: 6.6 K/9), so his walk rate and groundball rate are very important to any kind of success he has on the mound. He struggled early in his career with the Giants because he struggled with both. He threw 116 2/3 innings between 2003 and 2005 and walked almost five batters per nine innings (4.6, to be exact) while serving up 21 homers in the same span (1.6 HR/9). He was a decent prospect, but he bounced between San Francisco and their Triple-A affiliate in Fresno for three years before finally sticking with the big league club in 2006. He pitched exclusively in relief in 2006 (he previously bounced between the rotation and the bullpen), but he had a good year because he cut the walks down to 2.4 per nine innings and because he sliced his home run rate by about a third to 0.6 HR/9.
Upon closer inspection, though, you could interpret that good year in 2006 as lucky. His batted ball profile barely budged from 2005 to 2006; his groundball rate actually dropped from 36.7% to 34.1% and though he cut down on his line drives a bit, it wasn’t a dramatic change from 24.4% to 21.8%. He was certainly pitching better and the walk rate attests to that, but in 2005, 17.1% of his flyballs went for home runs and in 2006, just 5.4% landed over the fence. That’s the sort of change that isn’t necessarily sustainable, and so it wouldn’t have been a mistake to expect a bit of regression from Correia in 2007. Indeed, his walkouts rate went up a bit, his strikeout rate went down, and his home run rate went from 0.6/9 innings to 0.8. Still, he was obviously a much better pitcher in 2007 than he’d been in 2003-2005, and this time his lower home run rate had a solid groundball rate to go with it; he got grounders at a 45.1% rate.
The Giants moved him to the rotation in 2008, and he didn’t do well at all there. His walk rate ticked back up to 3.8 BB/9 and his strikeout rate dropped to a career low 5.4 K/9. He served up 15 homers in 110 innings and his groundball rate dropped back below 40%. In a nutshell, he found some success in 2006 by dropping his walk rate and he found some in 2007 by getting ground balls and he didn’t do any of those things in 2008. As a result, he got non-tendered by the Giants and moved south to San Diego.
2009 was his big year in San Diego and it’s not hard to figure out how he did it. His walk rate dipped back below 3.0/9 and his homer rate dipped under 1.0/9. His groundballs stayed up at 44.8%. He pitched in a hitter’s park, but his FIP (3.81) was lower than his ERA (3.91) and his xFIP (4.20) was respectable, too. Nothing groundbreaking, but if the Pirates could certainly have used a pitcher capable of pitching that well over 198 innings in 2010. Unfortunately, Correia didn’t duplicate that season last year. His walk rate crept back up towards 4.0 and his homer rate sky-rocketed back up to 1.24 HR/9, both of which contributed to his 5.40 ERA. The huge jump in homers was a bit strange, though; his groundball rate actually went up to 48.9%, the best rate of his career, and his line drive rate stayed about where it’s always been (21%), which would seem to indicate that he wasn’t getting hit all that much harder last year. Instead of 7.8% of his flyballs landing over the fence (his 2009 HR/FB rate), they went over at a 14.8% clip.
What’s generally concerning to me about Correia is this: in Correia’s three best years, his FIP has been substantially lower than his xFIP. FIP is an ERA analogue calculated from strikeout rate, walk rate, and home run rate with a league specific factor; xFIP is very similar except that it estimates home run rate from flyball rate (the basic concept is that two pitchers with 40% flyball rates should give up home runs at about the same rate and if they don’t, the ballparks in which they pitch are one reason why), which helps adjust for different parks. It’s easy to look at those numbers and see how AT&T and Petco helped Correia out.
But if we use xFIP to point out how his home field helped him in 2006 and 2007 and 2009, we should also use it to point out how weirdly flukey his bad year last year looks. That high home run rate seems way out of place with his groundball and line drive rates staying static and it wouldn’t be a surprise at all to see him cut down on the home runs, despite moving to the more balanced PNC Park. As stated above, he’s not a strikeout pitcher, but his strikeout rate is higher than Paul Mahom (5.6 K/9), Zach Duke (4.7 K/9), and even Ross Ohlendorf’s K-rate with the Pirates (5.9 K/9), which means that he should still at least have some buffer between himself and the Pirates’ defensive meltdowns, should he keep pitching at career rates.
So what happened last year? It’s possible that his PitchFX gives us a clue. Correia’s slider had a vertical break (Quick refresher! Vertical break is measured by PitchFX as where the ball crosses the plane of the plate relative to where it would cross with no spin. Remember, there’s no such thing as a rising fastball, but fastballs typically have positive vertical break values because the spin on a fastball keeps the ball higher in the zone than it would naturally be. Curveballs on the other hand, have negative break values because the spin on a curveball causes the ball to drop more than it normally would. Sliders tend to have slight positive vertical break numbers; the league average over the past few years is generally between 1.5 and 3.0) of 2.0 in 2009, but it jumped to 3.9 in 2010. In other words, his slider stayed up in the zone a a bit more last year. It’s impossible to say that was the reason for his struggles (he’s had similar slider numbers in the past though never quite as high as 3.9) and using FanGraphs’ new heat maps his 2010 sliders don’t look hugely different from the 2009 edition. Of course, comparing the two heat maps by eye is subjective; Correia struggled last year was with home runs, it would make a lot of sense that he left his slider up in the zone a bit too often.
The bottom line is that yes, Correia got help from Petco in 2009 and from AT&T Park in 2006 and 2007 that PNC Park likely won’t afford him. And yes, his 2008 season was truly awful, but I’m not sure his 2010 season was as bad as it appears by just looking at his ERA and adding in the fact that he pitched at Petco. If Ray Searage can keep him throwing strikes and work on his breaking pitches to help him keep the ball on the ground, I wouldn’t be overly surprised if he had a bounce-back year with the Pirates in 2011. That’s a lot of ifs, mind you, given the concerns laid out in the first paragraph, but I don’t think that it’s impossible.