Neftali Feliz to the Rotation: Will He Shine Under the Texas Sun?

It looks like moving relievers into the rotation has been the trend of the off-season. Last week, I tried to forecast White Sox pitcher Chris Sale‘s performance as a starter next season. With the news that the Rangers have signed Joe Nathan to be their closer, incumbent closer Neftali Feliz becomes the flavor of the day in reliever-turned-starter land. Will his transition go as smoothly as rotation-mate C.J. Wilson’s did, who made the switch in 2010, or will he wilt under the Texas sun with the heavier workload?

Though on the surface Feliz had another fantastic season as the Rangers stopper, his skills truly took a tumble. His K% plunged 19%, while his BB% jumped 78% and he continued to allow a ton of fly balls. This all led to SIERA/xFIP marks near the 4.00 level and an xFIP- of 105.

There is some good news, however. His velocity remained stable and his SwStk% and ClStk% only declined slightly. Basically, if he would have remained in the bullpen, it would have been easy to project his strikeout rate to rebound. Control was also a problem, but this time a drop in F-Strike% backs up the increased walk rate. Though he had posted excellent walk rates during his first two seasons with the Rangers, he struggled with his control at several minor league levels, so this problem just reared its ugly head again, rather than manifested itself suddenly. That’s a positive, I think, as it is always tougher to try to explain sudden changes in skill level. Though his career BB/9 still remains about league average, I would estimate that he’s currently closer to a true talent level a bit higher than that, as his 2009-2010 BB/9 rates were much lower than his F-Strike% marks would have suggested.

So now let’s try to figure out what Feliz may do in the rotation. As discussed in the Sale article, starters typically lose two to three miles per hour off their fastball after making the conversion from a reliever. Feliz averaged 96.3 MPH with his fastball the last two years, so he still should end up averaging around 94.0 miles per hour, which is excellent. Next, let’s assume that Feliz’s K% would have rebounded to around 25% next year. Since pitchers lose about 15%-20% of their K% upon moving from the bullpen into the rotation, Feliz is looking at a strikeout rate of around 8.0.

Along with a K/9 decline, Feliz’s BB% and BB/9 should improve as well. Applying the same 15%-20% drop to an expected 2012 walk rate as a reliever (let’s go with 3.4) gives us a rate around 2.8. His batted ball profile may change as he has thrown around 80% fastballs the last two seasons. Obviously, that is not going to happen as a starter. This could increase his ground ball rate a bit, which will be important in the summer heat. Still, he will remain a fly ball pitcher, but maybe not as extreme as he was as a reliever.

Since I enjoy looking at other pitchers with comparable skill sets to give us a better picture of what kind of pitcher Feliz may be, I found Tom Gorzelanny in 2011 (I know, I know) as almost an identical match. His SIERA was 3.68, which sounds like a very reasonable projected ERA for Feliz. Between he and Sale though, I do prefer Sale, as his strikeout rate may be a bit better, and he has a huge advantage in ground ball rate. He should also come cheaper, which is another plus.