He may have to prove that Sunday in one of the team's biggest games of the year – a divisional rival matchup with the Green Bay Packers, a team that has the same 4-4 record as the Vikings but already beat Minnesota in the season opener.
With Allen suffering a sprained right AC joint (shoulder) on Sunday against the Houston Texans, Robison may get his first opportunity to start since filling in for Ray Edwards during his four-game suspension to end the 2007 season.
"I feel like if either one of them go down I should be the guy that steps up and starts at that spot or anything like that. I definitely feel like I'm the third defensive end," Robison said. "Probably most of my time's been spent playing the left side of the line. I haven't played a whole lot of snaps on the right side. I've played a little bit here and there, but most of my snaps at ends have been the left side."
Robison has also started rotating inside more often on passing downs to add quickness across the defense line, but if Allen is unable to play on Sunday, Robison, a fourth-round draft choice in 2007, is the most obvious candidate to assume the duties at right end.
He didn't seem to think conditioning would be a problem for him if he had to take on the additional snap counts of a starter.
"As far as I'm concerned, I'm ready to take on a full-time role right now," he said. "I feel like if either one of those guys weren't here I'd be the starter right now and I'd be just fine. But obviously they are here so I know my role and I've just got to keep playing it."
"That's the way it happens in the league. Guys get hurt and the other guys got to step up. If you're going to play, the other guys have to step up," said defensive tackle Pat Williams.
Allen hurt his shoulder in the first half of the Vikings' 28-21 win Sunday and returned to play much of the second half after reportedly taking a pain-killing injection at halftime. Head coach Brad Childress and several of Allen's teammates called him a tough guy for doing that.
"You know what? Each game I think guys play through something, whether it's a sprain, a tear, a pull, a bruise," safety Darren Sharper said. "This day and age, the NFL is so rough and the game is so violent that I think each player is playing through something during the game. Whenever you're a tough guy – like all of our guys are; Jared is a tough guy – you can push through things like that."
Williams said he knew Allen was hurting because he plays next to him, but he also said, "That's the way it goes – play hurt."
Allen did that, registering his second sack in the fourth quarter, pulling down quarterback Sage Rosenfels with one arm.
According to Scout.com's Adam Caplan, Allen's AC sprain could just be a day-to-day injury if it is only a Grade 1 sprain. A Grade 2 sprain could have Allen sidelined one to three weeks and a Grade 3 sprain could put him out of action for at least four weeks. We should find out more about the extent of the injury Wednesday.
Robison wasn't aware of Allen's injury right away.
"At that time we had no clue. I saw him get dinged up a little bit," Robison said. "That's the thing about this league. At any point in time you've got to be ready to go. We didn't really know the extent of it too much. Just got to be ready for whatever happens."
Ironically, one of the most athletic plays of the day was Robison hurdling high over a would-be blocker on his way to hurry a quarterback throw on Sunday.
"I thought the guy was going to cut me so my plan was just to jump over him. As soon as I jumped I saw he wasn't cutting and I'm just glad that I didn't get hit and fall on my head or anything," he said. "Usually a guy will come up and you'll see his shoulders dip. It's kind of an instinct thing. You've got to kind of know what you're looking at. I thought he was going to cut me, so I jumped."
For the season, Robison has yet to register a sack but is credited with five quarterback hurries, tied for the fifth on the team.