Where Did Jair Jurrjens’ Grounders Go?

Yesterday, Zach Sanders unveiled NL Starting Pitcher Rankings for the 2011 season. Braves righty Jair Jurrjens was ominously listed under the “Doubt” tier. And there are reasons to have doubt about the 25-year-old: Jurrjens is coming off an injury-wracked 2010 in which his Expected Fielding Independent Pitching (xFIP) climbed for a third straight year. The former Tigers farmhand has whiffed and walked a similar number of batters over that time frame, but Jurrjens’ plummeting ground ball rate should have you thinking twice before drafting him.

Jurrjens’ ERAs over the 2008-2010 seasons suggest he was very good in ’08 (3.68 ERA), Cy Young-worthy in ’09 (2.60) and mediocre in ’10 (4.64). His peripherals, on the other hand, show a downward trend: a 3.96 xFIP in ’08, 4.34 in ’09 and 4.47 during a 2010 season shortened by left hamstring and right knee injuries. Jurrjens’ K rate hasn’t changed much at all, ranging from 6.36 to 6.65 batters per nine innings over the past three years, and his walk rate has sat between 3.14 to 3.35 per nine. But check out his ground ball and fly ball rates:

2008: 51.5 GB%, 26.5 FB%
2009: 42.9 GB%, 39.1 FB%
2010: 39.9 GB%, 41.9 FB%

The MLB averages are roughly 44% for grounders and 28% for fly balls, so Jurrjens has gone from a strong ground ball pitcher to a guy whose pitches get lofted often. Trading grounders for flies is rarely a positive for a pitcher: according to Baseball-Reference, the NL average slugging percentage on fly balls last season was .584 (Jurrjens’ was .582). Ground balls have a higher BABIP than fly balls, but it’s pretty hard to get an extra-base hit on a two-hopper to the shortstop (grounders had a .259 slugging percentage). More fly balls means more damage in the form of doubles, triples and homers.

Coming up as a prospect, Jurrjens was lauded for the downward, grounder-inducing action on his fastball and changeup. Here’s what Baseball America’s Bill Balew said after the Braves acquired Jurrjens and Gorkys Hernandez from the Tigers for Edgar Renteria leading up to the 2008 season:

Jurrjens goes after hitters with a two-seam fastball with plenty of a sink or a four-seamer that ranges from 92-95 mph with late life and armside run. He has good arm speed and sinking action on his changeup.

At first, Jurrjens did indeed get grounders with his fastball and changeup. But that hasn’t been the case over the past two seasons. Dave Allen was kind enough to queue up his Pitch F/X database and break down the changes in ground ball rate for Jurrjens’ pitches over the 2007-2008 period and 2009-2010. While the ground ball rate on his third pitch, his slider, has increased (though it’s still below average), Jurrjens is getting far fewer grounders on his fastball and change:

Fastball

2007-2008: 49%
2009-2010: 43%
MLB AVG (four-seamers and two-seamers): 42%

Changeup

2007-2008: 54%
2009-2010: 46%
MLB AVG: 50%

Slider

2007-2008: 35%
2009-2010: 38%
MLB AVG: 45%

There’s generally an inverse relationship between pitch height and grounders: the higher in the zone the pitch is, the fewer ground balls batters hit. Also courtesy of Dave Allen, here are Jurrjens’ pitch heights on his fastball and changeup. The red line is Jurrjens from 2007-2008, and the blue line is 2009-2010. The Y axis shows pitch height, and the X axis shows the frequency at which pitches were thrown at that height. First, the fastball:

The 2009-2010 blue line is shifted up, indicating that Jurrjens has thrown his fastball higher in the zone over the past two years. He’s also leaving his changeup higher in the zone:

That changeup has been the biggest bugaboo for Jurrjens. While the slugging percentage on balls in play on his fastball hasn’t changed much, checking in at .487 from 2007-2008 and .493 from 2009-2010 (.540 MLB average), the slugging percentage on his off-speed pitch has jumped from .436 from 2007-2008 to .502 from 2009-2010 (.452 MLB average).

ERA aside, Jurrjens’ underlying performance has dipped three years running. He doesn’t strike out many hitters, and while his control is above-average, he won’t be confused with Roy Halladay on that front. In order to be a quality starter with those strikeout and walk rates, Jurrjens needs to keep the ball down. With an 8.8 percent HR/FB rate last year, Jurrjens served up about one home run per nine innings. Should his HR/FB rate inch up closer to the 10-11% MLB average, with his fly ball rate remaining so high, Jurrjens could get whiplash this season.

Perhaps he’ll regain those groundballing ways in 2011 with a stronger, healthier lower body. If he doesn’t, though, don’t be surprised if Jurrjens’ ERA remains above four.

MLB average ground ball and slugging percentage on balls in play by pitch type totals courtesy of The Hardball Times’ Harry Pavlidis.