Most people here will probably disagree, but I think if McCallum boxes like he did against Watson and in the first two Toney fights, then he'll beat Valdez on points.
I'd actually also pick McCallum over 12 (he never went 15); great chin and endurance with plenty of ring savvy, I think he'd be able to weather some rough patches and box and counter his way to a points victory.
Valdez was an intangible; was he really that good? I never like it when best performances are defeats... McCallum was the real McCoy, as a Jackson, Curry, Watson or indeed a Collins will testify too.
McCallum by decision. Valdez isnt gonna knock out the iron chinned McCallum, and he damn sure wouldnt outbox him.
Valdez takes time off to re-charge at times; McCallum is busy. Valdez has serious power; McCallum had a great chin. McCallum by decision. Bad matchup for Valdez IMO
He did go 15 once against Sean Mannion and 13 against Luigi Minchillo. All of his junior middleweight title fights were scheduled for 15 rounds.
I guess I'll be the one to go for Valdez. If he can hurt Briscoe he can hurt McCallum. If he can hang with Monzon over 24 rounds in narrow losses then he should be able to turn the trick against The Body Snatcher. If Tony can fight in spurts and win a decision over a busier McCallum I think Valdez can as well.