E.J. Henderson confident he will be OK by Sunday

Based on a similar experience from last November, Vikings Pro Bowl middle linebacker E.J. Henderson said he's "pretty confident" he will play in Sunday's home opener despite missing practice Thursday and Friday because of a sore and swollen left knee.

"I think we had one episode last year where it swelled up a lot," Henderson said. "We pretty much had to do the same thing -- drain it, treat it and I made it out there Sunday. This is nothing out the ordinary. Just maybe a little more swelling, a little more pain, but it's something that we're dealing with, and hopefully I'll be ready to rock on Sunday."

Henderson had fluid drained from the knee Thursday and said he was feeling better Friday. An X-ray on Thursday revealed no structural damage.

Coach Leslie Frazier is cautiously "hopeful" that Henderson will play but called it a game-time decision based on a pregame workout at the Metrodome before the team plays the Tampa Bay Buccaneers. Officially, Henderson is listed as questionable, meaning he has a 50 percent chance of playing.

"The swelling is down, so that was a good thing," Frazier said. "But he still looked tender. ... When he said that he was struggling a little bit, you have to pay attention because he never talks about injuries at all. It's not who he is. If there's anybody who can play through things, E.J. Henderson can."

Overnight, the Vikings went from being injury-free coming out of Week 1 to potentially losing a starter at the position with the least depth.

Jasper Brinkley, a reliable backup the past two years, had hip surgery and was placed on injured reserve two weeks ago. That forced the Vikings to scramble after making their final cuts Sept. 3.

The move would be a significant change for Erin Henderson. He has just one NFL start, which came on the weak side last Sunday.

"Your vision has to be a lot different and your responsibility is a lot different [at middle linebacker]," Frazier said. "You're calling the defense, you're getting people lined up. You're making sure that the front is where it should be, so there's a lot more responsibility in that role as a middle linebacker."

Frazier said there's still a possibility that strong-side linebacker Chad Greenway will call the defense and line people up.

Onatolu, meanwhile, has no NFL starts. He also spent most of the preseason recovering from a broken foot and appeared lost in pass coverages in the preseason finale against Houston.

Onatolu would come off the field in the nickel, which the Vikings employ about 50 percent of the time. But that also means Erin Henderson would be asked to play about twice as many snaps.

Henderson said he believes the reduced number of preseason snaps combined with an inordinately high amount (77) in the regular-season opener might have contributed to the extra swelling and soreness.

"I've felt that swelling before," said Henderson, who practiced Wednesday. "I expected it to flare up a little bit. But just not that much."

Although Erin Henderson said he's ready to start in the middle, he doesn't think it will be necessary. Asked what he thinks are the chances of his big brother playing Sunday, Erin didn't hesitate.