Juan Castillo screamed the play dead, strutted to the line of scrimmage, and unleashed a profanity-filled tirade on the Eagles' first-round draft pick.

Fletcher Cox, welcome to the NFL.

"I don't know what I did," Cox said later. "But I said, 'Yes, sir,' gave him no lip back, and I just kept going."

There was some hollering and some hooting, but mostly there was instruction as the Eagles informally cut the ribbon on the 2012 season with the first day of rookie minicamp.

Until Saturday, most of the 45 players invited to camp were just names on a scouting report, images on a screen. But the two practices gave Eagles coaches their first up-close look at the team's draft picks and rookie free agent signings, even if the pace was a mandated light one.

Naturally, the spotlight was on Cox, the solidly-built defensive tackle who is supposed to improve the Eagles' pass rush.

Castillo, the second-year defensive coordinator, undressed the rookie in the afternoon session when it appeared as if he thought the 21-year old was loafing. In the morning, defensive line coach Jim Washburn - never one to mince words - got on Cox for not hustling upfield after he was blocked.

"I know that's one thing Coach Washburn is going to do," Cox said. "He's going to get after me, and that keeps me motivated."

But those moments were few between for Cox, and he came as billed. He looked quick off the snap for a 6-foot-4, 298-pound man. He showed strength when he split a double team and got in a quarterback's face during team drills. And he displayed versatility when Washburn briefly moved him outside.

Numbers may have had more to do with sliding Cox to end on Saturday. But it's something he did regularly at Mississippi State, and Washburn has been known to move his linemen all across the line.

"I played a lot of d-end," Cox said.

The Eagles' defensive draft picks stood apart - as they should - from a cast that included a dozen or so non-roster invitees. There was linebacker Mychal Kendricks, who ran with a tight end and intercepted a pass 30 yards downfield. There was defensive end Vinny Curry, who was a constant menace off the edge. And there was cornerback Brandon Boykin, who broke up pass after pass during one-on-ones with wide receivers.

Kendricks' interception was off Nick Foles, taken in the third round, while covering the 6-5 Brett Brackett.

The Eagles appear willing to give the rookie a first crack at the strong-side spot, especially if the 5-11 linebacker proves he can cover tree-sized tight ends.

"It doesn't matter," Kendricks said of his height disadvantage, "because at the end of the day I'm going to have to go out there and do it."

The 6-3, 266-pound Curry, who some analysts projected to go earlier than in the late second round where the Eagles snapped him up, appears tailor made to Washburn's wide-nine scheme up front and the veteran's coach's fire-breathing coaching methods.

He "was as good as advertised," Curry said. "Coach Wash is a crazy dude, but he means well."

Celek ready. Coach Andy Reid said Friday that veteran tight end Brent Celek will be ready for the start of the season. He is recovering from surgeries for a sports hernia and a torn labrum in his hip.

Contact Jeff McLane at 215-854-4745, jmclane@phillynews.com or follow on Twitter @Jeff_McLane.