Who is your cornerman?

Every boxer has a cornerman.  The cornerman’s job is to offer instruction and guidance during the bout.  He motivates the boxer to keep going in times of trouble.  He pats the boxer on the back when he thinks it is needed but he’s also willing to give the guy an earful as well.  He doesn’t care about what the reporters, the spectators, and the critics say.  His job is to do whatever is necessary to help the boxer be a better boxer.  Every boxer needs a good one.

My question to baseball coaches and players is this …

Who is your cornerman?