Of course he still is. Mac only threatened to go public with Dobson's belt. Besides which, what Gerrard covered up wouldn't cost him his job, it would just make him and Sinclair look bad.I don"t think Gerrard Back in season 4 because I think he's not officer after the last case with Mac..
There's no reason why Gerrard shouldn't be around, and I hope he is since a) Carmen Argenziano is an excellent actor and b) Gerrard's actually the victim of Mac's self-righteousness and inability to see that he was the one who screwed up. (Sorry, but Mac was 100% wrong in the Dobson case, and Gerrard and Sinclair's response was completely correct and proper, despite the writers' desperate attempts to make Mac out to be a victim of politics. He really wasn't.)