Meh, don't see him being an upgrade anywhere. We have good depth at MLB and Mays has never been all that productive. Denver isn't exactly stacked at LB, more so now that Miller is getting suspended. If he was worth a shit, I'd think they would have kept him...
I wouldn't be opposed to adding a quality veteran LB, I just don't think he's the guy.
We need playmakers at the LB position, and Mays has 1 forced fumble, 1/2 a sack and zero INTs in his 5 year career. For comparisons sake, DeAndre Levy, who isn't exactly a playmaker himself, has 2 forced fumbles, 1 sack and 5 INTs in his 4 year career.
An upgrade is certainly welcome at OLB, but I just don't see Mays being that upgrade...
Mays is slow for LB, he is solid against the run, but a liability on passing downs. I think the Broncos just wanted to give Irving a shot. He has more potential.