Plunk Everyone

So far this year, the American League East has been the prime battleground for plunk wars. Three of the top five team vs team match-ups, in terms of total hit batters, are in the American League east. Tampa Bay and Boston have hit each other 14 times, which ties them for the lead with Toronto and the Yankees who have also hit each other 14 times (but in 3 fewer games). Texas and the Angels are next with 13 plunkings of each other, and the Yankees-Red Sox match-up is behind them with 12. The Nationals and Marlins have also hit each other 12 times, but they've played 3 more games against each other than Boston and New York.

Teams	HBP	Games	plunks per game
Rays-Red Sox	14	12	1.2
Blue Jays-Yankees	14	9	1.6
Rangers-Angels	13	9	1.4
Yankees-Red Sox	12	9	1.3
Nationals-Marlins	12	12	1
Tigers-Indians	11	8	1.4
Brewers-Astros	11	9	1.2
Pirates-Cubs	11	12	0.9
Cardinals-Pirates	11	12	0.9
Red Sox-Orioles	10	12	0.8
Indians-Reds	10	6	1.7
Rays-Yankees	10	12	0.8

American League East divisional games are 2nd only to the National League Central in total hit batters, but the AL east trails the NL central by only 3 HBPs, despite the NL central playing 25 more divisional games (there are more divisional games in the NLC because they have 6 teams instead of 5). In terms of HBPs per game, the East division of the AL hits each other 22% more than the next most plunk prone division at a rate of 0.9 HBPs per game. That's 38% more than the average for any game that isn't an AL east divisional match-up.

Total HBPs in divisional games, by division:

Division	HBP	Games	Plunks per Game
NL Central	86	119	0.7
AL East	83	94	0.9
NL West	57	81	0.7
NL East	55	84	0.7
AL Central	49	93	0.5
AL West	37	59	0.6

Despite all this, there is a model for peaceful coexistence in the American League East - the Blue Jays and Rays have played 6 games without hitting each other at all. The only other divisional match-ups where no one has been hit yet this year are the Cardinals and Reds, and the Reds and Astros. But the Reds and Astros have only met twice so far. Perhaps the secret to the detente between the Jays and Rays is their rhyming names... but somehow I doubt the Yankees and Red Sox would ever be willing to sit down and work out their difference by changing their names to something that ends in "ays". On the other hand, the Jays and Rays still have to play each other 12 times, so theirs plenty of time for the peace to break down between them.

At this point in the season, no team-vs-team match-up appears to be on pace to hit each other as many times as the Yankees and Red Sox did in 2004. They bounced 33 pitches off each other that season, and no other pair of teams has plunked each other that many times since sometime before 1960 - if ever. And as if that wasn't enough, they hit each other 8 times in the ALCS.