But will his knees hold up?

Good question

He needs to keep the speed that made him an edge rusher to be feared.

I fear the dude running around in a thong with a jar of mayonaise. Speed got nothing to do with it.

So maybe that's why he is going through drills at practice? To get fast again??

I think so.

Depends on whether he makes his own mayonaise of buys it in a jar.