DAVIE, Fla. – The Miami Dolphins have a key injury in the secondary before the start of training camp. Second-round pick Xavien Howard will be placed on the physically unable to perform list this week with a knee injury, head coach Adam Gase said Tuesday.

Howard was injured last month during the final day of mandatory minicamp and had his knee scoped, according to Gase. However, Howard is expected to be ready for the start of the regular season.

The rookie was projected to be a Week 1 starter at a thin position, but those plans could change depending on how long Howard is sidelined.

“He will be out for a little bit. We expect, at worst, that he will be ready by the first regular-season game,” Gase said. “He’s been working hard trying to work his way back.”

Backup cornerback Tony Lippett will get an extended look with the starters in training camp. Lippett and Howard rotated back-and-forth with the first team in the spring opposite No. 1 cornerback Byron Maxwell.

The depth behind Lippett is a concern for Miami to start training camp. Second-year cornerback Bobby McCain will continue to work primarily as a slot corner, while other corners such as Tyler Patmon, Chimdi Chekwa and Ifo Ekpre-Olomu compete for roster spots.

“It is what it is right now,” Gase said. “[Howard] is not going to be there. So it’s a bunch of guys with a chance to step up and see who wants to try to make this team.”