Baltimore Ravens defensive tackle Haloti Ngata tweaked his hamstring during a conditioning test on Thursday and missed the team's first practice of training camp, CBSSports.com reported.
"We're going to take it slow and make sure he's OK," coach John Harbaugh said.
The injury isn't considered serious, but Aaron Wilson of the Carroll County Times, citing a league source, reported late Thursday that Ngata has been placed on the active physically unable to perform list.