Edwin Jackson’s Struggles a Desert Mirage

A mid-90’s fastball. A biting, mid-80’s slider. A sturdy 6-3, 210 pound frame. Since his days as a prized Dodgers prospect, Edwin Jackson has been touted as a potential ace. However, Baseball America’s number four prospect prior to the 2004 season wore out his welcome in L.A. and wallowed in mediocrity as a Tampa Bay Ray.

Shipped to the Tigers in December of 2008, Jackson finally began to break through with a 3.5 WAR season in 2009. He joined his fourth organization this past winter as part of “The Big Trade,” with Jackson and Ian Kennedy going to the Diamondbacks, Austin Jackson, Max Scherzer, Daniel Schlereth and Phil Coke Detroit-bound and Curtis Granderson headed to the Bronx.

While a healthy, resurgent Kennedy is producing, Jackson’s 2010 season seemingly conjures up memories of his vexing Dodgers and Rays days. After surrendering five runs and getting taken deep twice in 7.2 innings pitched against the Blue Jays on Saturday, the 26-year-old righty owns a 6.28 ERA over his first ten starts. Jackson acquired the “underachiever” label over the years, with his results often falling short of his stuff. But beneath that ugly ERA, he has basically been the same guy who held his own in Detroit last year.

In 61.2 innings, Jackson has struck out 7.74 batters per nine innings, nearly a whiff per nine higher than his 2009 mark (6.77 K/9). He has issued 2.92 BB/9, almost identical to his walk rate with the Tigers (2.94 BB/9). And, after posting a 39.1 percent ground ball rate in ’09, Jackson has induced a grounder 47.3 percent of the time in 2010.

Jackson got a swinging strike 9.8 percent of the time as a Tiger, with a 79.2 percent contact rate. As a D-Back, he has garnered swinging strikes 11 percent and has a 76.1 percent contact rate (the MLB averages are roughly 8.5 percent and 81 percent, respectively). He’s also getting ahead in the count or inducing first pitch contact more, with his first pitch strike percentage rising from 54.5 percent in 2009 to 57.5 percent this season (58 percent MLB average).

Some of these “improvements” are due to Jackson’s switch from the American League to the National League. Derek Carty over at The Hardball Times conducted a study of pitchers switching leagues between 2004-2008 and found that AL pitchers going to the NL improved their K/9 by +0.57, decreased their BB/9 by -0.05 and lowered their RA/9 by -0.42. That helps explain the increase in Jackson’s K rate, swinging strikes and first pitch strikes, as well as his lowered contact rate. At worst, though, we could say he’s pitching as well as in 2009 and perhaps a bit better.

Sadly, that good work has been obscured by a bad luck trifecta of a lower-than-usual rate of stranding base runners, a high batting average on balls in play and an inflated home run per fly ball rate.

His LOB rate of 63.3 percent is well below his career 70.9 mark. Jackson has a .332 BABIP this year, compared to a .311 career average. He’s keeping the ball on the ground more, and grounders do have a higher BABIP than fly balls. It’s also true that Arizona’s infielders aren’t known as defensive wizards: 3B Mark Reynolds (career -7.6 UZR/150), SS Stephen Drew (-9), 2B Kelly Johnson (-5.3) and 1B Adam LaRoche (-3.4) all rate poorly by Ultimate Zone Rating. Even so, balls in play probably won’t continue to elude leather quite so often.

It’s also highly unlikely that Jackson continues to serve up so many homers. When hitters loft the ball, it’s leaving the park 16.4 percent of the time. Jackson’s career HR/FB rate is 10.2 percent, and the MLB average is about 11 percent.

Chase Field has a four-year HR/FB park factor of 106, meaning that closer to 12 percent of fly balls leave the yard in Arizona (taking the Chase HR/FB factor and multiplying it by the rate at which fly balls become home runs, 11 percent). So far, Jackson has been taken deep on eight of his 41 fly balls at home (19.5 HR/FB percentage). If Jackson had a 12 HR/FB percentage at Chase, he would have surrendered three less dingers–five, instead of eight. On the road, Jackson has given up a homer on two of his 20 fly balls (10 HR/FB%, close to the MLB average). While Jackson has served up 1.46 HR/9, that number “should” be about one per nine innings pitched.

While Jackson’s ERA might have Diamondbacks fans ready to label him a bust, he’s pitching as well as he ever has in the majors. His xFIP, based on K’s, walks and a normalized home run/fly ball rate, is 3.87. That ranks in the top 20 among NL starters tossing at least 50 innings. Jackson’s no ace, but he still looks like a solid starter after frustrating talent evaluators for years.