Two in line to replace Birk

Vikings offensive lineman Artis Hicks sat two stalls down from Matt Birk in the Vikings locker room the past three years and became good friends with the veteran center.

Hicks echoed the sentiment of many fans Wednesday when he expressed disappointment after Birk signed a free-agent contract with the Baltimore Ravens, ending his 11-year tenure with the Vikings.

"I know this had to be hard for him," Hicks said. "I know it was a hard decision for him to pack up his bags, so to speak. He had a long career here, a very good career here. He's from here. But it's always a business. You learn that very fast in this league."

Birk's departure dealt an emotional blow to the organization, but it also leaves a significant hole in the middle of the offensive line. Though he turns 33 this summer, Birk is a six-time Pro Bowler who still plays at a high level, and it won't be easy to replace him.

The Vikings must decide whether Birk's replacement will come from inside or outside their locker room. John Sullivan, a sixth-round pick from Notre Dame last year, will move to the top of the depth chart. Sullivan, who spent his rookie season learning under Birk, said after the season that he believes he's prepared to step in and become a starter.

"I learned a lot just about the NFL," he said. "I learned how it works, and I learned a lot from Matt about the center position. He was a great teacher for me, a great resource, and I think it was really valuable for me here as I continue my career."

Vikings coach Brad Childress made note of Sullivan's football knowledge when asked about his progress during the NFL scouting combine last month.

"John Sullivan is a guy that football is important to," Childress said. "He's a smart guy. I will say he's the first guy that has been back in the building [this offseason]. I don't know if he got bored in Connecticut or what. I looked up one day and he's on the treadmill. I go, 'What the heck are you doing in here?' He's got A) football IQ and he wants to be good, and he talks it and Matt [Birk] has been very giving in terms of not sweating him, just sharing."

Right guard Anthony Herrera also could be a candidate. Herrera played center in 2005 during training camp and the preseason. Right tackle Ryan Cook played center in college, but it seems unlikely the Vikings would move him.

"I think Sully is very capable of stepping in and become a starting center based on what he showed last year," Hicks said. "Herrera had a breakout year and has all the qualities to be a center. I don't know what direction we'll go, but I think both of those guys can handle the job."

No matter who gets the job, Hicks said it will be different without Birk next season.

"Me and Matt have become pretty close over the last three years. and we're obviously going to miss him a lot," Hicks said.

• Free-agent linebacker Heath Farwell visited the Cleveland Browns on Wednesday, a day after he visited the New England Patriots. The Patriots, Browns, Vikings and two other teams are in the mix for his services, according to a league source.

• Childress left Wednesday for San Diego, where he will attend his son's graduation from the Marine Corps this week.

• Hicks returned to the Twin Cities to begin intensive rehab after having surgery to fix a torn right triceps six weeks ago. Hicks said the surgery was successful and he expects to be ready by training camp.