"I've been kind of partially amazed that he could do what he's done," Kelly said recently, per Phillymag.com. "... There was one day here, you can check with him, I think he went from here to an Army training session and went out and had a couple PT tests that he had to pass and actually one of them was a five-mile test. He nailed it and came back and didn't miss a day.
"He's been just a guy that you see every day just getting a little bit better, getting a little bit better. As I said the other day, a real intriguing prospect but just amazed at everything that Alejandro does to be honest with you."
Villanueva's size and versatility -- he played offensive guard and tight end at Army -- offer compelling options for the outside-the-box thinking Kelly.
The 25-year-old, however, has a steep climb to make the Eagles' roster, battling Fletcher Cox, Cedric Thornton, Vinny Curry, Brandon Bair, Joe Kruger, Taylor Hart and Frances Mays at the defensive end position.
"For me, it's all uphill and that's the way I have to look -- is just up," Villanueva said last week. "So hopefully this work that I've put in during this offseason will pay dividends in training camp."