ARLINGTON, Texas -- Scott Diamond's retaliation fastball that whizzed behind Josh Hamilton's head during Thursday's game has earned the Minnesota Twins' left-hander a six-game suspension.

Joe Garagiola Jr., Major League Baseball's senior vice president of standards and on-field operations, announced the discipline Friday just as the Texas Rangers and Twins started the second game of their four-game set. Diamond, whose suspension was to begin Friday night, will file an appeal, MLB said in a statement.

Diamond threw at Hamilton in the bottom of the third inning as payback for Rangers starter Roy Oswalt plunking Twins catcher Joe Mauer on the upper back in the top of the inning.

Hamilton, who ended up with five RBIs in the Rangers' 10-6 win Thursday, said he wasn't surprised to be the target of retaliation, but that he didn't expect to get one up by his head.

"I don't think he was trying to hit me in the head," Hamilton said prior to Friday's game. "I just think the ball got away from him. But it got away from him and it was close. That's probably the closest I've ever had a pitch come to me where I could feel it go behind the back of my neck."

Diamond was ejected from the game after sailing the pitch by Hamilton. He had allowed two runs on three hits and a pair of walks in 2 1/3 innings.