WHIFF PROFILE: AARON HEILMAN
On Wednesday, the Mariners and Cubs brokered a three-player deal involving one of the biggest trading chips of the offseason, Aaron Heilman. His stock bottomed-out following a tumultuous 2008 season, when he and the rest of the Mets bullpen seemed destined to fail every time out. Heilman finished with a 5.21 ERA and a 1.59 WHIP, allowing 38% of inherited runners to score.
One ugly season aside, Heilman has always been an effective reliever with the ability to spot a few starts. The former 1st-round pick is unquestionably talented, with a plus arm and stuff that jumps off the pages of the WHIFF charts:
Fastball..... 93.387.... 0.185....... 0.48....0.453.....80
Slider........ 84.155.... 0.481....... 0.42....0.195.....97
Those are WHIFF-rate percentiles of 80, 97, and 90, respectively. It is very, very rare for any pitcher to feature their entire repertoire in the upper quartile, let alone have two pitches in the top 10 percent. Heilman's bread-and-butter has always been his fastball-changeup combo, but it would've been difficult to predict his slider (a pitch he rarely threw in previous seasons) developing into killer (.195 SLG% against). The .481 WHIFF rate puts it only a couple spots below the gold standard sliders of Brad Lidge (.509) and Joba Chamberlain (.506).
Breaking down Heilman's repertoire a little further, we see there are some blemishes beneath the swing-and-miss allure. Heilman is consistently pitching outside of the strikezone. The InK% (In-Strikezone rate) of each of his pitches is below league average. Usually, a leading indicator of a breakout season is a newfound killer pitch with a strong InK%. It's safe to say Heilman has the killer pitches, but he's depending on hackers to chase them, rather than attacking within the zone.
Heilman does, however, compare very favorably with a guy who is now his teammate, Ryan Dempster. Like Heilman, Dempster was in starter/reliever limbo heading into last year, carrying the same "unreliable" tag after a rather disastrous season in relief. Both throw essentially the same three pitches (Dempster throws a unique split-change hybrid), with similar WHIFF structure:
Ryan Dempster - 2007
Fastball..... 92.041.... 0.127.......0.48....0.519.....38
Slider........ 86.326.... 0.316.......0.47....0.356.....53
Like Heilman's slider in '08, Dempster's splitter shot to the top in '07. He threw this pitch close to 600 times in '08, allowing him to neutralize LHBs over the course of 206.2 innings. Heilman has the same weapons to get hitters out from both sides of the plate if he gets a crack at starting this season.
It's up to the Cubs. Many baseball observers have noted Heilman's delivery--specifically, his high elbow inversion and near-sidearm angle--as major handicaps to becoming a successful innings-eater.
Heilman, at the very least, can be an adequate swingman. He's got the change of scenery he wanted, now we'll see about the results. WHIFF says his 2009 campaign is a real good bet to look more like his 2005-2007 seasons than the one he had in '08.