The incident happened in the eighth inning of Sunday's game.
Boston Red Sox second baseman Dustin Pedroia (knee, ankle) said he expects to return to the Red Sox starting lineup Wednesday.
As is typical for just about all MLB-issued suspensions of this nature, Barnes is appealing the suspension, so he will not begin to serve any games until he receives a hearing at a later date. He will be able to pitch during the process.
Barnes was suspended for four games, but many have been calling for such actions to draw harsher punishment so as to deter it in the future.
Joe Torre, MLB's chief baseball officer, announced Sano's suspension Monday. "That's kind of a line you don't cross".
From the Boston dugout in Baltimore, Pedroia could be seen telling Machaco "That's not me" after the Orioles third baseman was almost plunked by Barnes, and called it a "mishandled situation" following Boston's win. If I slid into third base and got Manny's knee, I know I'm going to get drilled. There was zero intention of him trying to hurt me; he just made a bad slide (when) he did hurt me (on Friday).
After the Barnes pitch, Pedroia was seen on TV explaining, "It's not me" to Machado.
Barnes was ejected Sunday after sailing a fastball past Machado's helmet at Baltimore.
Manager John Farrell said after Tuesday night's game was rained out that his injured second baseman would have been able to play after missing the previous two games. I think when you're talking about throwing at guys' heads, that can affect their lives.