Vikings safety Husain Abdullah heads toward Tuesday's start of free agency knowing full well that he's among a group of players who will be scrutinized a little bit differently in today's NFL.

Although he's a young, experienced and improving player, Abdullah also has suffered four concussions the past two seasons. He's been cleared by a host of medical personnel, including two of the country's leading concussion specialists, but he also knows his market value could be hurt by the same changing culture that probably helped him avoid a more serious concussion.

"I can definitely see why it would hurt," Abdullah said. "Concussions get all the attention. It's the hot topic. The NFL has increased the awareness of concussions and how it protects the players from coming back too soon. So that's going to be the first thing teams want to look at if you have a history of concussions."

Abdullah wants to re-sign with the Vikings, a team that took a chance on him as an undrafted free agent out of Washington State in 2008. The Vikings are interested but have been frank about their concussion concerns in a league that now has a strict return-to-play protocol.

"In today's NFL, it's a factor," coach Leslie Frazier said. "You can't ignore concussions anymore. It's rare now that a guy gets a concussion and doesn't miss a game, it seems. So you have to consider that part of a player's history today. That's just a fact."

Concussions aside, the Vikings have praised the 26-year-old Abdullah. They like his intelligence, work ethic and thorough knowledge of how to play either safety position. And although Abdullah hasn't reached Pro Bowl caliber, the Vikings believe he can advance a career that includes 57 games played, including 24 starts the past two seasons.

Abdullah's career was put on hold Nov. 29 when he landed on injured reserve 15 days after suffering his fourth concussion in about 15 months. A concussion earlier in the season hadn't caused him to miss a game, but a second one about a month later left him unable to clear his head for weeks.

As he watched his teammates play the final seven games of a 3-13 season, Abdullah admits he was scared. He also admitted to reporters a day after the season that he was considering retirement rather than risk the long-term cognitive damage that has been linked to repeated concussions.

"I was definitely considering it," Abdullah said earlier this month. "That's why I went to Pittsburgh. I felt if I was going to continue playing, I had to talk to the best specialists I could find."

In January, Abdullah went to see Dr. Micky Collins and Dr. Joseph Maroon, two nationally renowned concussion specialists based at the University of Pittsburgh Medical Center. They examined him, tested him, advised him and finally told him the news he needed to hear before he ever reached for another helmet again.

"They said it wasn't career-threatening," Abdullah said. "They said it wasn't as serious as I thought it was. It was a big relief because I wanted to keep playing, but I would have retired if they had told me I should stop playing."

It's a decision more players find themselves wrestling with as the awareness level increases. Not everyone feels they can make the same choice Abdullah made.

San Diego Chargers guard Kris Dielman is one of them. He was 31 and in the prime of his career. But he walked away from $5.5 million this season and potentially a lot more in next year's free-agency period. A concussion last Oct. 23 against the New York Jets and an ensuing seizure suffered on the flight home was simply too much for him to ignore.

"I've got to get out when the getting out's good still," Dielman told reporters at his retirement news conference. "It wasn't worth what would happen if I would have kept on playing."

Abdullah isn't the only free agent whose concussion history will be scrutinized. Others who have a history of concussions include Jacksonville Jaguars defensive end Matt Roth and Jets safety Brodney Pool.

Abdullah said one of the reasons he wants to return to the Vikings is he trusts how the coaching staff and head athletic trainer Eric Sugarman and his staff handle concussions. He also likes that some of his close friends on the team have been able to notice his concussion symptoms quickly and alert the medical staff.

"The Vikings did a great job of recognizing I was banged up and got me out of games," Abdullah said. "Some guys get a concussion and go back in, and that's when they get the hit that ends up being the huge blow that really causes damage. I'm thankful to the Vikings for that and, obviously, that's a factor for someone like me when it comes to where I want to play."