When asked about his unnecessary-roughness penalty shortly after last week's 12-10 preseason loss to the Chargers, Vikings rookie safety Harrison Smith said, "There's stuff that sometimes you can't control."

The NFL disagreed Friday. And it's going to cost Smith a $21,000 fine when he gets his first NFL paycheck next week.

The hit on Chargers receiver Mike Willie came in the closing moments and extended the Chargers' game-winning drive. The nature of the hit made it probable that Smith would be out some money once the league got around to reviewing the matter.

"He unnecessarily struck a defenseless player in the head and neck area with his shoulder," league spokesman Randall Liu explained in an e-mail.

After the game, Smith tried to describe the split-second thought process that comes with playing safety in a league that's making it more difficult for defenders to hit offensive players.

"I thought maybe I could go for the ball, then I realized I should go for the hit, so I kind of got caught in the middle," Smith said. "I wish I didn't get the penalty. Maybe I could have played it differently. I'll watch the film. It's easy to watch on TV and say, 'You should hit him here or there.' ... At the end of the day, football is football."

Youth movement continues Of the 53 players on the Vikings' roster, 29 are 25 years old or younger. That's 54.7 percent of the roster.

There are eight rookies and 16 more entering either their second or third NFL seasons in the NFL. Defensive tackle Trevor Guyton was the only player from this year's 10-man draft class to be waived. Guyton, however, seems to be a prime candidate to be added to the eight-man practice squad when it's assembled Saturday morning.

Of the 10 players from the 2011 draft, nine are still on the roster. The only one missing is Ross Homan, a sixth-round pick who was cut before last season.

Love placed on IR The Vikings placed second-year offensive tackle DeMarcus Love on injured reserve, expecting him to need surgery on a lingering shoulder/pectoral injury. As a rookie last season, Love was inactive for all 16 games. He was expected to supply some depth at left tackle behind Matt Kalil, though starting left guard Charlie Johnson would also be an emergency option there. The only other backup tackle on the roster right now is Pat Brown.

Seven linebackers kept Linebacker wasn't considered a position of great depth this year, but the Vikings still kept seven, including surprise rookie seventh-round pick Audie Cole.

Cole made it as the third middle linebacker behind Jasper Brinkley and Tyrone McKenzie. Cole's knack for making big plays this summer was highlighted in the 36-14 victory over the Bills in Week 2 of the preseason. With the Vikings leading 22-14 late in the game, Cole returned interceptions for touchdowns on back-to-back plays from scrimmage.

Vikings trade for corner The Vikings traded undisclosed draft picks for Cardinals cornerback A.J. Jefferson, a third-year player who began the 2011 season as the starter opposite standout rookie Patrick Peterson, the Arizona Republic reported late Friday.

After struggling early on, the 6-1, 190-pound Jefferson was moved to the sub defensive packages. He had one interception and 12 passes defensed in 16 games with seven starts.

The Vikings kept six corners when they trimmed their roster to 53 players earlier in the day. One of the corners cut was Chris Carr, by far the most surprising cut of the day. Carr is 29. Jefferson, at 24, is more in line with the Vikings' youth movement.

The Vikings will have to release a player to make room for Jefferson.

Roster might not be set This won't be the "final" 53-man roster. In addition to releasing someone to make room for Jefferson, waiver claims will be announced at 8 p.m. Saturday. By virtue of their 3-13 record last season, the Vikings are third in line for any waiver claims they submitted.

Players with fewer than four vested seasons are subject to the waiver wire. Others that are released are free to sign with any team.

Teams also can make trades before setting their opening day roster.