And it continues...
Yeah, that would be the Youkilis-Joba feud.
With Joba Chamberlain on the mound, and Kevin Youkilis at bat, Chamberlain threw a fastball right at Youkilis's head, sending the first baseman down. The ball actually hit Youkilis's bat on the play, and brought him up staring at Chamberlain.
Home plate umpire Marty Foster warned both sides, and both Terry Francona and Joe Girardi came out to get explanations. There was no rushing the mound, but there's clearly a history here.
Youkilis eventually struck out swinging.