Defensive tackle Haloti Ngata tweaked his hamstring during his conditioning test and missed the first practice of training camp on Thursday.
The injury isn't believed to be serious and the Ravens are exercising precaution with Ngata.
"We're going to take it slow and make sure he's OK," coach John Harbaugh said.
Also absent from practice on Thursday were wide receiver David Reed (ACL), offensive lineman Kelechi Osemele (back), offensive lineman Jah Reid (calf) and defensive end Pernell McPhee (knee). With those four still out of practice, there have been no changes to the PUP list.
Follow Ravens reporter Jason Butt on Twitter: @JasonButtCBS and @CBSSportsNFLBAL.
