He's talking about Al Pitrelli.
Well, Guitar_God, I don't think Pitrelli is a shitty guitarist. Maybe he didn't fit into Megadeth as Marty did, but he was in Savatage too. And, I heard "Rude Awakening", the live album of Megadeth, and he can play Marty's solos pretty good. The only thing to complain is that in solo writing, at least for Megadeth's songs, Marty was more succesful than Al.