Analyzing Andy Sonnanstine's Move To The Bullpen

A former starter on the Rays' 2008 team, Andy Sonnanstine has faded into his role as a long-reliever. Heck, at times I forget Sonnanstine is still an active member of the roster. As long as his role remains the same, I doubt we'll talk about Sonnanstine much this season.

But this one's for you, Sonny.

Looking at his average leverage index - measuring the accuity of the situations he's pitched in - it's no wonder why we haven't mentioned him much. His average leverage index (pLI) is 0.32 (1.00 is average, above is high leverage, and below is low leverage). His gmLI, or the leverage index when he enters the game, is 0.35. Nine of his 15 appearances have come with a run margin of four or more, and 73 of the 88 plate appearances that involve Sonnanstine have come in situations considered low-leverage.

Congratulations, Andy. You are now the white flag.

Now that Sonnanstine has settled into his role a bit, we should be able to tell if there are any drastic changes from Sonny the starter to Sonny the reliever.

In a small sample size of 21 innings in relief, Sonnanstine's statistics haven't changed all that much.* In terms of ERA, his 3.43 ERA in 2010 looks very nice compared to the 5.30 career, but looking at things like FIP (fielding independent pitching) and xFIP (expected fielding independent pitching), we see there has been a bit of luck - both good and bad.

*Note that some of those innings came in semi-starting roles i.e. filling in for the injured Jeff Niemann after just 1.1 innings.

Looking at peripheral stats, his K/9 of 5.57 is actually less than his 5.95 career number, while his 2.57 BB/9 is more than his career 2.07. Neither set of numbers is spectacular, but at the same time not terrible. Although Sonnanstine hasn't seen a big change in control rates, his FIP of 5.20 is below replacement level, and over a half run higher than his career 4.42 FIP. The high FIP is a product of home runs allowed.

Sonny has allowed four home runs in just 21 innings of work (1.71 HR/9). His career HR/9 is also high at 1.25. However, his home run-to-fly ball ratio of 15.4% this year is over five percent more than his career number of 10.2%Using xFIP, which neutralizes home run rates, his 4.41 xFIP in 2010 is slightly less than his career xFIP of 4.47.

With his overall numbers pretty steady, let's now look at his pitch selection and batted ball data. Despite havinng an elevated line-drive rate of 23.2% (18.0% career), Sonnasntine's BABIP of .245 is .75 points lower than his .320 career BABIP. This somewhat explains the lucky difference in ERA and FIP. Sonnantine also has stranded more runners than he did as a starter, but that is to be expected as a reliever.

When it comes to pitch selection, Sonnanstine is still using four-to-five pitches but he has all but abandoned a regular fastball. He is throwing a cutter 53.9% of the time and a straight fastball just 16.4%. This has been a gradual shift over the past few seasons. The good news is he has a positive pitch value on the cutter, and is getting a strike with the pitch nearly 70% of the time (including whiffs, fouls, and balls in play). His slider, curveball, and change-up usage remain around career norms.

Velocity wise, all of his pitches remain within a mile per hour of where they have historically been. He is getting ahead in the count more than ever (68.2% first-pitch strikes in 2010, 61.2% career), and hitters are chasing his stuff out of the zone nearly 30% of the time, both of which are promising signs.

Interestingly, while most of the numbers have remain similar, Sonny has changed his release point:

2009

 2010

Images from texasleaguers.com

I could go in a million different directions from here, but since the stats remain pretty neutral, I'll assume - at least at this point - that any change in release hasn't mattered in regards to result.

In conclusion, Sonnanstine's role with the team may have changed, but not much has changed about Sonnanstine.