Who Is David Aardsma?

Perhaps the only bright spot in last night’s game was David Aardsma‘s return to the mound after two years recovering from Tommy John surgery. As fans, it wasn’t exactly what we all hoped for, J.P. Arencibia homered on the first pitch he saw, but there was also plenty to like. At points, we witnessed some of the command issues, rust, and likely over-throwing we’d expect from a guy that worked his tail off for the last two years, but we also saw plenty of called strikes and whiffs.

Aardsma’s role plays up bigger in 2013, but he can still provide some bullpen relief in the last week of baseball. There was always high risk in this pickup, but now that he’s healthy, we can wait and hope for high upside. In his previous two seasons with the Mariners, he collected 69 saves, a 2.90 ERA, a 9.6 K/9, and a 6.1 H/9. While he has a premium fastball that limits hits and draws whiffs, he’s prone to walk a few batters, resulting in a 4.4 BB/9 from 2009-2010. The walks give him a less favorable FIP than he’d otherwise deserve, a 3.01 in 2009 and a 4.05 in 2010.

The other issue with his style is his high flyball rate. If the 53.9 FB% in 2009 carries over into 2012/2013, he could see an increase in homerun rates switching from Safeco to Yankee Stadium. Although his flyabll rate went down in 2010, the number was still relatively high at 44.9%, and it’s caused by a four-seam fastball dominant pitch selection. In 2010, he used a 78% four-seam selection, and backed that up with just 9% sliders, 11% splitters, and 2% curveballs.

Four-Seam Fastball

Again, his four-seam fastball is the cornerstone of his pitch repertoire. Keep in mind the microscopic sample size of 13 four-seam fastballs from his one appearance so far, but the movement is nearly identical to what he showed two years ago. While I’m optimistic about the fastball showing the same strong rising action with good bite into right handed hitters, he saw a dip in velocity. It’s an average of 2.5 mph, and if this remains when the sample size grows, it’s a significant drop. I would keep in mind that the velocity may increase as he gets more work with his new elbow; he’s only a couple months removed from a setback after all. That said, the movement on the fastball is still impressive, and should play well over the last week if he can locate it without the common Tommy John surgery control issues.

Slider 

Out of his three pitch repertoire, the slider is the weakest. It’s mostly used against right handed hitters to counter the fastball. The 10 mph speed change obviously helps after he’s showcased his fastball, but the movement away from RHH prevents them from making good contact. He only sported a 6.67% whiff rate on it in 2010, so it’s not your typical strikeout slider, but it does prevent righties from sitting on the fastball.

Last night, he threw just 4 of them, showed slightly less cutting and sinking movement, but half the pitches resulted in whiffs. There was again a velocity drop, but it’s hard to make much out of just 4 pitches.

Splitter 

Aardsma threw splitters just 11% of the time in 2010 and earned a 15.7% whiff rate. As the slider was his secondary pitch to right handers, the splitter is his secondary pitch to left handers. It couples good velocity with good movement, and can be a high leverage pitch due to an average strikeout rate and a very strong groundball rate. The downside is that lefties hit a lot of linedrives off the pitch in his last year, and it’s the worst batted ball type you want in an important situation. A positive, is that these linedrive numbers were strictly from 2010, and hopefully this is just another result of small sample size.

In his Yankee debut, he threw the pitch 7 times and accounted for 1 whiff. The velocity was slightly down again, but the movement remained. It maintained the same horizontal movement that hitters can’t decipher from the fastball, but it didn’t have the same sinking action.

Now that he’s pitching in Yankee Stadium, his secondary pitches will probably be more prominent thanks to a flyball heavy four-seam. Personally, I think there’s a lot of hope in that splitter, and maybe Freddy Garcia can teach him the swung-splitter.

Overall, Aardsma showed a lot of positives amongst a couple flaws. His line isn’t pretty thanks to Arencibia, but he worked incredibly hard for his late season return and pitched too well not to get some love. The hope is that he becomes a late inning reliever next season, and joins the Rivera/Robertson/Chamberlain trio. For now, he’ll earn a few more innings to prove he’s still got it this season, and I suppose there’s a very slim chance we’ll see him in the playoffs.

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