ALAMEDA, Calif. -- Raiders interim coach Tony Sparano expressed some concern over the health of Brian Leonhardt after the backup tight end suffered a concussion for the second consecutive week.

Leonhardt was hurt sometime early in the first half of Sunday's 52-0 loss to the St. Louis Rams. He played only five snaps on offense and seven on special teams before heading to the sidelines for good.

"That's a concern," Sparano said Monday. "We'll have to see. It'll be a long week that way because we don't have the extra days. We had extra days last week with both he and Latavius (Murray). In this situation here, we really don't have that kind of time and it's two weeks in a row so it's a concern for us."

Leonhardt also suffered a concussion against the Kansas City Chiefs on Nov. 20. An undrafted free agent who spent all of 2013 on the Raiders' practice squad, he has six catches for 35 yards and one touchdown.

Oakland is already thin at tight end. Last week the team placed David Ausberry -- the projected starter heading into training camp -- on injured reserve. With Leonhardt also hurting, second-year player Mychal Rivera is the only healthy tight end on the Raiders' roster.

Murray, who sat out the loss to the Rams a week after having a breakout game running the ball, still has yet to pass the NFL-mandated testing for concussions.

"We're still not there yet," Sparano said. "We're close, but we're not there yet, so I'm hopeful."