Joel Peralta and Foreign Substances

In Tuesday night’s game against the Tampa Bay Rays, Nationals’ manager Davey Johnson asked home plate umpire Tim Tschida to examine the glove right-hander Joel Peralta for foreign substances.

Peralta was subsequently ejected for having pine tar on his glove.

This is not new. Baseball has a long history of players skirting around the rulebook in hopes of gaining an edge on their opponent. Whether it is spitting on the baseball, taking performance-enhancing drugs, corking bats, cutting the baseball, or even just (allegedly) having a man in white standing in the outfield bleachers, cheating is as much a tradition in baseball as hot dogs and cracker jacks.

As they say, if ya ain’t cheatin’, ya ain’t tryin’.

In regards to Peralta, it seems as if Tuesday night was not an isolated incident for the right-hander. Davey Johnson spoke of rumors that Peralta liked to utilize pine tar to tip the scales in his favor on the mound. How did Johnson know the rumor to be valid? As he said in the post-game interview:

“Well, he pitched here. I don’t think it’s a secret.”

Peralta pitched for the Washington Nationals in 2010 and enjoyed the best season of his eight-year career, posting a 2.02 ERA and 3.02 FIP in 49 innings of work. At that time, his 9.00 K/9 strikeout rate marked the highest rate of his career. In many ways, he was reborn as a major-league reliever and has since become a solid set-up man for Tampa Bay.

No one knows when the 36-year-old began smearing pine tar on his glove. Judging by the comments given by Davey Johnson after the game, however, it seems exceedingly probable that he was doing so while in Washington three years ago.

Perusing his statistics, one thing really jumps out when trying to ascertain what changed between the 2009 season, in which Peralta compiled a 6.20 ERA and 4.72 FIP for Colorado, and his breakout 2010 season and beyond. His ability to generate swings-and-misses on his fastball has increased dramatically. Between the 2008 and 2009 seasons, Peralta only generated 6.1% swinging strikes on his fastball. Between 2010 and 2012, however, that number jumped to 10.1%. If we isolate that range to simply the 2012 season, his swinging-strike rate on fastballs is even higher at 16.4%.

What happened to his fastball? It did not gain more velocity. In fact, Peralta has lost almost a mile per hour since the 2010 season. The percentage of pitches thrown in the strike zone is lowest of his career this year, too, which suggests he is getting by more on deception and swings outside the strike zone. Could pine tar help facilitate this increased effectiveness?

On the less-skeptical side, perhaps the success of his fastball can directly be tied to the increased success of his split-fingered fastball. Over the past three seasons, Peralta has generated a swing-and-miss 20.3% of the time with his splitter and has consistently increased his usage of that pitch in every single season in the big leagues. It has become a true wipe-out pitch for him on the mound. Opposing batters would naturally swing later at and be fooled more by his fastball if they had his splitter in the back of their minds.

Setting up his fastball off his splitter is a plausible explanation for the increased effectiveness of his fastball, as well as his increased effectiveness as a whole. Perhaps we need not look any further than that. Still, it’s interesting to discover that Joel Peralta has purportedly used pine tar (at least) since the 2010 season because that just happens to coincide with his turnaround as a major league reliever.