The Red Sox added a pair of prospects to the system recently with Andrew Miller and
Rich Hill.  Both are former top prospects in their respective systems and both have huge control issues.  Miller is still struggling with that at Triple-A this year with 32 walks in 40 innings pitched.  Hill though has been converted to the pen and made a large improvement in his control.

While watching his last appearance I felt compelled to look up his pitch f/x because I felt he threw a ton of curve balls.  I was right and this season in 7 innings he has thrown 68 percent curve balls.  This looks like a change he made in his move to the pen as he was around 30-35 percent curves thrown as a starter.

I can understand why he might try this after reading some of his early scouting.  Here is some comments from John Sickels at MinorLeagueBall.com in a review of Hill in 2007:

He was erratic in college, dominating at times with his big-breaking curveball, but struggling to locate his average fastball.

The numbers agree as his fastball has a run value of 0.12 per hundred pitches.  That’s not very good and needs another pitch to help out.  Well I wouldn’t read much from his numbers this year in only seven innings, but it has worked so far.  His run values per hundred pitches on the curve stands at 5.49 and he has yet to allow a run.

There is another change that Pitch F/x is picking up as his fastball is no longer being classified as a four seamer but now a two seamer.  That gives a pitch to break the opposite way and help unbalance the hitter.  Here is an overhead look at the two pitches and how they would effect the hitter.  Two notes – Look how far left his release is and also those sliders seem to be curves that got incorrectly classified.

Like I said that release point is extremely far right.  So far right it’s also something new for him.  Here is a plot of all his release points since April of 2009.  Notice the large group high and about one foot to the right of center.  That is his old release point, but now he is going to the sidearm and the release point is about 4 feet to the right.

The trouble with relievers of course is trying to tell what is real in such small sample sizes.  Since moving to the pen in 2010 with the Sox his control has made a huge leap with walk rates currently in the mid 2’s.  This season he has dominated hitters too with a 12.86 K/9.

There is surely some regression headed his way, but we have no base line for him since all his historical data is based on a fast ball pitcher and not the curve ball one we are seeing.  There is also no one to compare him too.  In 2011 only one pitcher has thrown more than 50 percent of his pitches as curve balls.  Jason Bulger of the Angels has 58 percent curves, but his numbers are not as good as Hill.

My biggest concern is will this be short term success for Hill. Will hitters be able to figure out his curve ball and start putting it in play? I don’t know the answer to that, but with his big break I’m guessing it won’t be solid contact.  They will have to start swinging though as he is hitting the zone 64 percent of the time, which is above the league average for curves at 57 percent.

It’s difficult to say where Hill will go from here since his entire repertoire is new and he has added about 2 mile per hour more velocity than any previous season.  When someone changes their release point, primary pitch, velocity and usage there is no real way to accurately predict how they will do.

I don’t think this would be something he could do if he went back to starting, but in the bullpen he could become the extra arm the Red Sox need.  For now I would limit him to LOOGY duty, but so far he has been solid against both lefties and righties.  With the struggles we have seen in the pen this year it’s nice to see someone else besides Jonathan Papelbon doing well this year.

*This data was totalled before his appearance Sunday night when he totalled 2 strikeouts in an inning pitched.