John Sullivan was getting word through Brandon Fusco that some reporter was asking around about Joe Berger.

"Our 'Jack of All Trades,' " Fusco, the Vikings' injured right guard, said to Sullivan, the starting center.

"Nah," said Sullivan. "He's more like our Nine of Hearts."

Fusco and Sullivan laughed. So did Berger, the career backup sitting quietly at the locker next to Sullivan.

Whatever card he is, it's hard to imagine another NFL player being more valuable for a longer period of time while drawing less outside attention than Berger has since graduating magna cum laude with a mechanical engineering degree from Michigan Tech in 2005.

"It's hard for me to place a value on what I do," said Berger, who will make his third consecutive start at right guard in Chicago on Sunday. "In my mind, I just come to work and do my job. You know?"

Berger was a high school tackle in Newaygo, Mich. After that, he was a decorated Division II right tackle who started 28 games at a college that tried to disband football. If not for some deep-pocketed alumni stepping in to save the program, Berger guesses his 10-year NFL career — and counting — never would have happened because he had no intentions of leaving Michigan Tech without that degree.

"Math and science were kind of my thing in high school," said Berger, who had a 3.8 grade-point average at Michigan Tech. "I loved getting that degree, and I've kind of looked into what I can do with it after football. Maybe it's owning a business or working as an engineer. But it's really hard to nail that down as long as I'm still playing football and don't really have to nail it down."

On a team that went through a dramatic youth movement after last season, Berger, 32, and defensive tackle Tom Johnson, 30, are the only backups older than 30.

"I don't put a timetable on how long I'll play," Berger said. "If I'm healthy and there's a spot for me, why would I stop?"

In 2005, the Panthers selected Berger in the sixth round. He knew by then that his days playing tackle were over.

"I was told I didn't have the foot quickness that the tackles have in the NFL," Berger said. "The Panthers cut me in training camp. I went to Miami, where [longtime NFL offensive line coach] Hudson Houck started working with me at center. That put me ahead of the learning curve."

Berger played in only four games with no starts for the Dolphins from 2005-06 and the Cowboys from 2006-2008. He returned to Miami in 2009 and started six games for injured center Jake Grove.

A year later, Berger beat out Grove. That forced the Dolphins to cut Grove after paying him $14 million for only 12 games in Miami.

Berger signed with the Vikings in 2011 and started seven games. When Sullivan was hurt, Berger started a game at center. When Anthony Herrera went down, Berger started four games at right guard. When Steve Hutchinson broke down, Berger started two games at left guard.

The 2012 season came and went without a start. Then last season presented one start at each guard spot.

All was quiet this season until the 3:49 mark of the first quarter at Buffalo in Week 7. That's when the Vikings ran a play that knocked both Sullivan (concussion) and right guard Vladimir Ducasse (knee) out for the rest of the game. Before the next play was snapped 36 seconds later, Berger was at center and tackle Mike Harris was at guard.

"That's kind of my niche, going in when I'm needed," Berger said. "How do you do it? You just do it."

A week later, with Ducasse still ailing, Berger started at right guard. He played well in a victory at Tampa Bay and supplanted a healthy Ducasse for another win against Washington.

With the team riding its first winning streak since the end of the 2012 season, Berger will make his 32nd NFL start (eighth at right guard) in his 90th regular-season game on Sunday.

On the field, Berger is the adjustable wrench that coaches covet with only 46 active players on game day. Off the field, Berger naturally spends his free time piecing things together.

"As a kid, I loved Legos and just building things," Berger said. "I have a wood shop at the house. I've made some chairs and a nice side table that we use. I just like making a pile of parts look like something nice."

Mark Craig mark.craig@startribune.com