The 49ers Sign Washington Defensive Tackle Sebastian Valdez as a UDFA

This guy has a legitimate chance to make the 53-man roster one day.

The 49ers have signed Washington defensive tackle Sebastian Valdez as an undrafted free agent according to reports. Valdez is the third defensive tackle the 49ers have added to their team this week. The other two are Alfred Collins (Round 2) and C.J. West (Round 4).

Collins and West each weigh more than 320 pounds while Valdez is much smaller -- just 301 pounds. And yet, he plays much bigger than his size. Like Collins and West, Valdez is a run-stuffing specialist who anchors quite well against double-team blocks, which means he's a great fit for the 49ers' Wide 9 defensive front.

Valdez is extremely athletic and powerful for his size -- he ran a 5.02 40 and a 4.46 20-yard shuttle plus he put up 34 reps on the bench at his Pro Day.

So why did he go undrafted?

That's because Valdez has 31 1/4-inch arms. There are very few NFL offensive linemen with arms that short.

So while Valdez can take on double teams and hold his ground, he'll struggle to disengage from blocks and make tackles. Essentially, he's a human boulder on the football field. That's why he went undrafted.

Still, it's nice to have a human boulder as a backup if the starting run stuffers get injured. The 49ers clearly want to have a dominant run defense and Valdez will give them depth. Look for them to stash him on their practice squad.