Will 2011 Be A Jonathan Papelbon Rebound Year?

First of all, let's see what the problem was with Papelbon: You don't need to be an advanced stats inclined fan to know that his fastball lost a lot of its effectiveness as his put away pitch and a look at the Pitch Value section at FanGraphs seems to confirm those observation:

• In 2008, Paps' heat was worth 2.21 runs per 100 fastballs thrown.
• In 2009, that same pitch value declined to 1.49 runs per 100 thrown
• In 2010, that value continued to decrease and was worth just 0.56 runs

What happened? The first thing that comes to mind is a loss of velocity, but the Pitch f/x data shows that this is not the case: He averaged 94.3 mph in 2007 (his best season) and was clocked at 94.7 and 94.9 mph in 2009 and 2010 respectively. In my opinion, the origin of the problem is the loss of "deceptiveness" in his delivery: If you remember, in 2009 Spring Training Jonathan Papelbon made a subtle but important change to the mechanics of his delivery. Here's what John Farrel said:

That change of delivery made the opposing hitters see the ball better coming out of the Red Sox closer's hand and swing less at fastballs off the plate:  here's the O-Swing% (Swings at pitches Out of the zone percentage) on Fastballs in the last  3 years:

For a pitcher who lives on inducing weak contact and whiffs on pitches out of the zone, losing some of the deceptiveness could be a major blow if adjustments aren't made. Papelbon's walks per 9 innings jumped to the 3+  range in the last 2 seasons and, when falling behind in the count, his FB up the middle got rocked as you can see  here:

Joe Lefkowitz's Pitch F/X Tool:

Side Notes: The green triangle is the only non-fastball HR that JP allowed. A hanging Splitter  that caught too much

of the plate and Colorado's PH J.Giambi (!!!!) sent it out of the Park. What a hectic road trip it was!

We can also see that most of the whiffs were on Splitters in the dirt: In fact, opposing hitters swung at 42.7% of Splitters out of the zone generating either swings-and-misses (65.6% vs RHH and 43.7% vs LHH) or ground balls (83.3% vs RHH and 52.3% vs LHH).

Looking at those numbers, it's clear that Papelbon should rely heavily on changing speed to regain the effectiveness of his fastball. Mixing pitches and giving the opposition different looks was the absolute thing to do for Papelbon to keep hitters off balance and it looks like he did made those adjustments as the season progressed.

I have put below Papelbon's DIPS monthly splits and his pitch type percentages: Although the samples we're dealing with are too small, the steady decrease of his Expected Fielding Independent Pitching (xFIP) indicates that things were heading in the right direction for him and the fact that he relied heavily on diversifying his pitch selection is the main reason* as the strong correlation here shows us.

*You need a proof that mixing speed is the biggest component of pitching? Tim Wakefield Fastball is one of the most effective pitches in Baseball!

Monthly Splits:

For instance, the ace reliever threw the most Splitters during the month of August. It's also during that month that he posted his best Fielding Independent Pitching (FIP).

Let's hope he keeps doing it next season because if he does, we may get our best bullpen acquisition by tendering him a contract.