oh him, he came in about 6 episodes to go. (this is all from memory of last year) He was shown in a couple spots in another department and after Kovak decided to step down as head of the ER he accepted the position.
I'm waiting to see how he pans out though as there have been several short lived non-ER stars show up for that position and most didn't last but a few episodes. But with the number of characters that have been cut in the last couple years he may well stay for a bit.