well, he signed the new contract sometime after the AS break last season, and while his average dropped quite a bit (.300 avg was unsustainable for him), he tried to offset him returning to "normal" by stealing like a madman. i don't know why he started stealing like crazy, but pre-ASB he had 17 SBs in 90 games, but 33 SBs in 70 games post-ASB. and he did most of his stealing batting 3rd.
we know he is not a .300 hitter, as he hit .258 post ASB after hitting .306 pre ASB. of course his value is the SBs, but i don't see him stealing 50 bases again. at best, in the 30-40 range but like i said don't forget he did a lot of his stealing after singing the new contract so it would be wrong to assume he stole those bases for a fat contract. his 20 HR power is pretty much real.
.278, 21hr, 35sb would be my optimistic projection, .274, 18hr, 30sb would be my safe projection. if you can get someone good in return, i would trade byrnes. imo, right now byrnes is at his highest possible value with a career year under his belt, no way he repeats his 07 numbers. sell high to a manager who will be impressed by those numbers; 20/50. 20/50 is something you expect from carl crawford, a first rounder.