Will The Real Guillermo Mota Please Stand Up?

November 25, 2005

By now we all know that Mike Lowell and Josh Beckett are headed to the Red Sox in exchange for Hanley Ramirez, Anibal Sanchez, Jesus Delgado and Harvey Garcia. But it was just announced the Red Sox insisted that Guillermo Mota be added to the deal, in exchange for even more players from Boston's farm system.

Mota is an interesting commodity. In 2003, and part of 2004, all with the Dodgers, he had an ERA near 2.00. Since being traded to the Marlines in mid-2004, his ERA has ballooned to 4.74.

So the question is, who is the real Guillermo Mota? The dominating setup man that helped the 2004 Dodgers win the N.L. West? Or the struggling reliever who was relegated to a reduced workload in the 2005 Marlins bullpen.

When I wrote Baseball Mogul, I realized that ERA isn't the best indicator of a pitcher's underlying ability. So I created a stat called Defense Independent Component ERA (aka DICE). DICE looks only at the events within a pitcher's control: Home Runs, Walks, Hit Batters and Strikeouts. It then uses these events to project that player's ERA. This gives us a number that looks like ERA, but with the bloop singles, great defensive plays and other random events removed.

DICE is pretty easy to calculate. We start with an ERA of 3.00 and modify it according to the walks, hit batters, strikeouts and home runs allowed by the pitcher:

DICE = 3.00 + (3*(BB + HBP) + 13*HR - 2*K) / IP

Mota's 2003 ERA was a tiny 1.97. Here's how we calculate his DICE for that same year:

2003 (LA): 26 BB, 1 HBP, 7 HR, 99 K, 105.0 IP

DICE = 3.00 + (3*(26 + 1) + 13*7 - 2*99) / 105.0

        = 3.00 + (81 + 91 - 198) / 105.0

        = 3.00 + (-26) / 105.0 = 2.76

So we see that Mota's actual 2003 ERA was more than 3/4 of a run lower than what we would expect from how he pitched.

Here's a table of his DICE over the past 3 seasons, along with his real ERA in each season:

Guillermo Mota: Defense Independent Component ERA (DICE)
Season Team BB HBP HR K IP DICE ERA
2003 LA 26 1 7 99 105.0 2.76 1.97
2004 LA/FLA 37 4 8 85 96.2 3.58 3.07
2005 FLA 32 1 5 60 67.0 3.66 4.70

As we can see, Mota's ERA in 2003 and 2004 was better than what you would expect from the underlying stats. It's no surprise that his ERA went up in 2005.

What is interesting is that Mota's 2005 DICE was virtually the same as his 2004 DICE. In other words, Mota's core ability appears essentially unchanged from 2004 to 2005. It's only the final outcome -- his ERA -- that went up by more than 50%.

Guillermo's struggles in 2005 appear to be due primarily to his defense and bad luck. If the Marlins had stuck with him and given him as many innings as he had in 2004, it's likely that his ERA would have moved closer to the 3.66 figure predicted by DICE.

What does this mean for the Red Sox? Will we see the 2005 Mota? Or a return to the 2004 edition? The question is misleading. Mota was essentially the same pitcher in 2004 and 2005. It's only the ERA that changed. Therefore, we should expect Mota to continue on the same path his been on for the last 2 seasons -- an above average relief pitcher capable of posting ERA's below 4.00.

That said, we should point out that both Dodger Stadium (in L.A.) and Pro Player Stadium (in Miami) are pitcher's parks. Pro Player has about 5% less offense than an average NL stadium. Dodger Stadium is roughly the same, with even a bit less offense. By contrast, Fenway is a hitter's park with about 5% more offense than average. This fact, combined with the shift from the National League to the American League, means it's extremely unlikely for Mota to match the numbers he put up with the Dodgers in 2003 or even 2004.

An ERA just under 4.00 is the most likely projection. Considering the troubles the Red Sox bullpen had in 2005, that still makes Mota a valuable acquisition.