The Vikings began their offseason strength and conditioning program at Winter Park last week and opened Wednesday's workouts to the media. So what all did we learn?

1. Henderson is the man in the middle

Now heading into his sixth season, Erin Henderson craves a heightened role. It just so happens the Vikings have an opening for a starting middle linebacker.

So now begins the spring experiment of pushing Henderson inside from the weakside position he's started at the past two seasons. Henderson said he'll be the starting middle linebacker when the team's organized team activities begin later this month. He's up to 249 pounds from his previous playing weight of 240.

"I know I'm going to have to have a little bit more lead in my pencil," he said.

As for any internal apprehension that moving Henderson inside might further expose his bad habit of wandering out of position while trying to make the big play, the linebacker has his response, believing gap control was a bigger deal playing on the weakside, when chasing the action was more dangerous.

"It's not really the same kind of situation once you move over to the mike [middle linebacker position]," Henderson said. "You still have to stay at home, still have to stick to your responsibilities. But I think they give you a little bit more freedom here at the mike to go find the ball and make plays."

2. Ponder avoided surgery on his throwing arm

Christian Ponder was "scared to death" he might have a blood clot when the injured right elbow that kept him out of the Vikings' playoff loss at Green Bay just randomly swelled up again in late January. A trip to the emergency room ultimately relieved his fear, but not before some anxious moments.

According to Ponder, the doctor who treated him feared he might have compartment syndrome, a potentially serious ailment in which a limb and even one's life can be at stake when the blood supply is cut off from muscles and nerves. Surgery was mentioned as a possibility during the diagnostic stage, Ponder said, but wasn't deemed necessary after a magnetic resonance imaging (MRI) exam.

"I had called Sugs [Vikings head athletic trainer Eric Sugarman]," Ponder said. "Luckily, he called [back] at the right moment and talked to the doctor and said don't do anything crazy. Just go get an MRI to make sure. And it ended up being fine. They were scaring me with what they wanted to do."

Ponder said he's now fine and has had no further lingering effects from the injury.

3. New receiver likes supporting cast

Long before free agency opened, receiver Greg Jennings, right, began diving into Vikings' film, concerned most with evaluating the skill set of Ponder. If Jennings was going to make a major move, he wanted to come away comfortable with his new quarterback. He did.

But Jennings also fell in love with the game-breaking abilities of Adrian Peterson, who repeatedly opened up the field by attracting eight defenders into the box. Most of all, however, Jennings was amazed at the Vikings' offensive line.

"Whoa," he said. "Man. When you watch film closely, I've never seen that. Adrian Peterson is Adrian Peterson. And he's the best back in the game hands down. But this offensive line might be the best in the game. They are dang good. And they know they're getting the box loaded up and getting all kinds of blitz looks. But to still create those holes and those creases, it's incredible."

4. Left tackle again trying to put on weight

When most guys take a break from working out, they gain weight. Vikings left tackle Matt Kalil took a break earlier this offseason and dropped to 280 pounds.

"For some other guys, they stop working out and they gain weight," Kalil said. "I shrivel up when I stop working out. I started a couple months ago and I'm getting back into it. I'm back to about 305. I'm probably looking to be 315 during the season, which shouldn't be a problem."

Kalil said he played last season at 310, except for a week late in the year when he dropped to 290 because of a three-day bout with pneumonia.

5. Vikings a 'good fit' for

new d-lineman

Defensive end Lawrence Jackson said the Lions offered him the same one-year, veteran's minimum deal [$780,000] the Vikings did last week. But rather than return to Detroit, Jackson decided a change was needed from the Lions' Wide 9 defensive scheme, which forces the ends to line up wider than they normally do.

"This just feels like it's a good fit with my skill set," said Jackson, who was drafted 28th overall by Seattle in 2008. "You look at what the Vikings' [top] three D-ends did last year. It was 32 [actually 28½] sacks and our guys [in Detroit] were not even 20.

"That was a huge factor and being able to watch Jared Allen every day to see what makes him great. That also was a huge factor."

In 32 games, including 24 starts, with Seattle in 2008 and 2009, Jackson had 6½ sacks. In 37 games with no starts for the Lions from 2010 to 2012, Jackson had 13 sacks.

Jackson said Oakland and Dallas also showed interest in him, but those teams wanted to wait until after the draft before possibly signing him.