If you actually watched the games Gio has pitched in, when he was struggling he'd get through 5-6 innings and give up 2-3 runs, Renteria would put him out there to give up a run and load the bases and he got 6-7 ER on his record instead of 2-3. It was bullshit.
EDIT: Fire Renteria. What a sorry excuse for a manager. Get on the 1st plane out of Chicago, and make sure it is a one way ticket.