Just listened to the Lowe Post where this was said,
http://www.espn.com/espnradio/play?id=23116874 (starts a little after the 55 minute mark for anyone who wants to actually hear it).
I don't think it was a head coach. Arnovitz said, "I had a really interesting conversation with a member of a coaching staff that I respect immensely..." (and to me personally I thought Arnovitz was saying he respected the coaching staff immensely, not necessarily this member of the staff he was actually speaking with, but that's open to interpretation). Anyway, if it was a head coach, I think Arnovitz would have just "coach" or "head coach" not "member of a coaching staff."
Considering how many assistants there are out there who have been grinding for years, and have yet to even sniff a head coaching job, and are maybe 5, 10, 15 years older than Stevens, let's just say I can see the possibility for a lot of sour grapes.
But actually, after actually listening to Arnovitz say it, I don't even think it sounded that much like sour grapes, more like "I think Stevens is great, but people are talking about him like he's already the greatest coach of all time, let's reel it in a little here." Similar to a possible sentiment like "Tatum is great, but some people act like he's going to be the greatest Celtic of all time, let's see him accomplish a little more before we put up his statue outside the Garden."