Ravens cornerback Jimmy Smith did not finish practice Thursday at the team’s training facility in Owings Mills.

During a full-team exercise, quarterback Joe Flacco threw a pass to rookie wide receiver Deonte Thompson, who ran an in route from the right side of the field. After the play was whistled dead, Smith was on the turf inside the Ravens’ indoor field on all fours. After a few minutes, he walked off slowly under the watchful eyes of two trainers and did not return.

It’s unclear what happened on the play, but after practice, defensive coordinator Dean Pees said Smith – who sat out almost all of the first five games after suffering a high left ankle sprain last season – may have hurt his back.

“I don’t know,” Pees said when asked about Smith. “I have to go in and find out. He just went down. I know he grabbed his back, but that’s all I saw. So I don’t really know the extent of it.”

Rookie outside linebacker Courtney Upshaw missed his fourth consecutive day of training camp with a bruised right shoulder. But Pees said he’s not terribly worried about Upshaw’s absence – yet.

“I’ll start getting worried if it’s halfway through the [preseason],” he said. “What we need to do is just get him out there – especially for some preseason games – and have him hit and get hit and actually play. It’s one thing to go out and practice. There’s different situations here in practice that are just not the same as game-type tempo and game-type situations, and that’s [why] we need to get him out there. I’m not too concerned yet until if we get down the road and he’s not playing in any games. Then I will be concerned.”  

Wide receiver Anquan Boldin was present and took part in some individual drills, but he did not participate in full-team exercises. Thompson was the slot receiver when the first offense went to a three-receiver set that also included Torrey Smith and Jacoby Jones.

Others who did not practice included: left guard Bobbie Williams (unspecified), defensive tackle Arthur Jones (unspecified), center Matt Birk (unspecified) , wide receivers Tandon Doss (hamstring) and Patrick Williams (unspecified), rookie running back Bernard Pierce (hamstring) and linebacker Josh Bynes (unspecified).

Tight end Dennis Pitta made his first appearance since breaking a bone in his right hand Monday and undergoing surgery the next day. Pitta wore a flesh-colored wrap around the hand and wrist and watched practice from the sideline.