Three things to watch at Cardinals rookie minicamp

TEMPE, Ariz. -- The Arizona Cardinals will begin a three-day rookie minicamp Friday, giving the first-year players their first taste of NFL football.

Additionally, the coaches will get their first impressions of the men trying to make the Cardinals' roster.

Here are three things to watch as rookie minicamp kicks off:

First-round proof: He has a few months until training camp, but D.J. Humphries needs to start showing why he’s capable of taking over for Bobby Massie at tackle this weekend. He came out as a junior and is only 21, but youth can be an excuse for only so long. He’ll be facing the trio of pass-rushers Arizona drafted -- Markus Golden, Rodney Gunter and Shaq Riddick -- and the coaching staff will be watching those matchups closely. If Humphries can handle them, his next challenge will be Calais Campbell.

The need for speed: J.J. Nelson is in a prime position to make a splash. He has the speed Cardinals coach Bruce Arians loves, and he’s entering a roster that’s without its fifth receiver (Ted Ginn was cut) and whose fourth receiver is still on the mend (Jaron Brown fractured his scapula). If Nelson can show that his receiving skills are on par with his speed, then a roster spot will be his to lose.

Gannon Sinclair has a shot: John Carlson’s retirement put the Cardinals on the hunt for another run-blocking tight end. It just so happens that they signed a 6-foot-7, 270-pound tight end. Coincidence? Probably not. But the next three days will be Gannon Sinclair’s chance to make a deep enough impression on Arians to be in the mix for a spot on the 53-man roster. Sinclair’s toughest obstacle, however, will be learning the Cardinals’ offensive scheme quickly enough to separate himself from the rest of the rookies. His collegiate stats show that Sinclair is effective in the red zone. As long as he can use that massive frame to block, he has a shot at making the 53.