It looks like it was Clements to me. Here's what the Chin had to say about the TC hiring:
"On the offensive side, I think everybody is very happy for Mike (Mularkey) and the opportunity that he now has as he becomes head coach in Buffalo. I know Mike wanted to take Kenny (Whisenhunt) or Tommy Clements with him as a coordinator and I was not, at the time, ready to be able to talk to either one of them and name either one of them. I wanted to talk to both of them at the time, so Tommy had the opportunity to go up there knowing he would have an opportunity here, but knowing he was offered a job as Mike got it. So, Tommy went with Mike as his offensive coordinator, "