MANKATO - The Vikings were bystanders in the first round of the 2008 draft after making the trade for Jared Allen. They had watched more players fall in the second round and feared that their target, safety Tyrell Johnson, would not make it to No. 47 overall.

Brad Childress did more business with his former boss in Philadelphia, Andy Reid, and the Vikings moved to No. 43 to land Johnson.

The reviews in training camp were excellent. And then Johnson moved into the starting lineup when Madieu Williams, an expensive offseason acquisition, suffered a fracture in his neck in training camp.

Williams missed the first seven games. The Vikings had few complaints over Johnson's play as a rookie starter.

"Madieu and I were real close,'' Johnson said. "We built a great relationship those first couple of years. Madieu's a class guy.''

Last week, Williams became the first casualty of the Vikings' salary cap issues when he was released. He signed with San Francisco.

Williams helped Johnson with his presence at the start of Tyrell's career, and now he could help with his absence as Johnson's long-term NFL status is about to be determined.

There are three contenders to replace Williams as the starter at free safety: Johnson, a high draft choice out of Arkansas State entering his fourth season; Jamarca Sanford, a seventh-round pick from Ole Miss entering his third season; and Mistral Raymond, a rookie sixth- rounder from South Florida.

You look at what the Vikings have invested as an organization and it's clear that they want Johnson to be the starter. Before that happens, they will have to see evidence that Johnson wants that, too.

Johnson started at strong safety alongside Williams in 2009. A grand season for the Purple wasn't so grand for the safeties. The Cover-2 approach asks the safeties to make the plays in front of them. Johnson and Williams failed to do that often enough for Childress to consider a change.

There was so much chaos in Mankato last August -- with Sidney Rice injured, Percy Harvin missing and Brett Favre hanging out in Mississippi -- that the fact Johnson's job was up for grabs received its ink on Page 8.

And when the competition ended, Childress went with Husain Abdullah over Johnson. Abdullah had been around for two years as an undrafted free agent and had received most of his attention for fasting in training camp because of Ramadan.

The word from the Vikings was that once Johnson lost his starting job he basically shut down -- doing what he had to do in practice, but nothing that would cause Childress to second-guess the decision.

"I was very disappointed in what happened ... the most disappointed I've ever been in my life as an athlete,'' Johnson said.

Johnson was talking Wednesday after the Vikings' morning practice. He had a few other comments that made it sound as if that disappointment was aimed both at himself and at the Vikings for basically phasing him out.

He plummeted from a 15-game starter in 2009 all the way to the inactive list for three consecutive games in October 2010.

On Wednesday, a reporter said to Johnson: "It sounds as if the Vikings want you to take Madieu Williams' job.''

Johnson said: "What they want is for me to step up and compete. That's what I'm going to do ... step up and compete. After that, I can't control the decision on who's going to play.''

Johnson was the free safety when Williams was hurt in 2008, and the strong safety in those 15 starts in 2009. Now, it's back to FS, but what the heck, Tyrell, the safeties are interchangeable in a Cover-2 defense, right?

"There are differences ... the gaps you cover are different,'' Johnson said. "In a Cover-2, it's not a case of the safeties being asked to make so many plays. One thing that might have hurt me was I had this idea that I should be making more plays.''

Such an idea leads to taking more chances, which leads to big plays for opponents, which leads to Johnson, 26, and a coveted acquisition by the Vikings, trying to regain his status as an NFL starter in Year 4.

"It's a defense where the rule for the safety is make the plays you are supposed to make,'' Johnson said.

Patrick Reusse can be heard noon-4 weekdays on 1500ESPN.