Vikings middle linebacker E.J. Henderson missed practice today because of a swollen knee, coach Leslie Frazier said after practice.

"It swelled up on him this morning," Frazier said. "It could have happened in practice yesterday. He went through all of practice and was fine. But woke up this morning and was sore. We thought it would be wise with his knee being sore a little bit to hold him back."

Frazier said the team will have Henders get an X-ray of the knee, but not an MRI.

"It's precautionary," Frazier said. "We'll see how he feels tomorrow when he wakes up. If there's a problem tomorrow, then you start getting a little more concerned."

The Vikings used Xavier Adibi and starting weak-side linebacker Erin Henderson at middle linebacker in practice. When Erin moved to the middle, Kenny Onatolu took over on the weak side.

Adibi was claimed off waivers from Houston on Sept. 4. He played inside linebacker in the Texans' 3-4 defense.

"He's become comfortable [in the 4-3]," Frazier said. "He played inside linebacker and some of the terminology they used is similar to ours. Some of the systems in the run game are a little different, but he's been with us a few weeks so he's becoming more comfortable."

Frazier said a decision between Erin Henderson or Adibi would be made Friday, if necessary.

Frazier also said defensive end Adrian Awasom, who missed his second consecutive day of practice because of a swollen knee, should be able to practice on Friday.

Also on the injury report for today: CB Asher Allen (toe) and WR Michael Jenkins (groin). Both had full practice participation.