Source: High ankle sprain for Seattle's Collier

Seattle Seahawks rookie defensive end L.J. Collier was diagnosed with a high ankle sprain after leaving Tuesday's practice with the injury, a source told ESPN's Adam Schefter.

The team's first-round draft pick left practice on a cart. He was blocking on a passing play when he went down in obvious pain.

"I just saw him go down. Looked like he was in a lot of pain," offensive tackle Duane Brown said. "I'm hoping he's alright. He's going to be a good player. I'm looking forward to working with him as well. Someone I think who has a lot of ability, a lot of potential. Still kind of raw in his technique, but I'm looking forward to working with him."

Collier refused help off the field from the training staff and walked off on his own with a pronounced limp.

Collier has not seen much time with the No. 1 defense during training camp, but the Seahawks have been expecting him to contribute right away along a defensive line that has taken some major hits this offseason with the trade of Frank Clark and more recently Jarran Reed's six-game suspension.

The Seahawks signed Ziggy Ansah in May to help account for Clark's departure. Ansah started camp on the active roster but has yet to practice, and the team believes he'll be ready around the start of the season.

The Seahawks' other edge players include Cassius Marsh, Rasheem Green, Jacob Martin, Barkevious Mingo, Quinton Jefferson and Nazair Jones. Seattle has also shown interest in former Packers outside linebacker/pass-rusher Nick Perry.

ESPN's Brady Henderson contributed to this report.