Former Vikings tight end John Carlson, a standout at Litchfield High who went on to play for Notre Dame, abruptly retired at age 30 on Tuesday. Per NFL.com:

It has been an offseason of early retirements, and Arizona Cardinals tight end John Carlson is next in line.

"After much thought and consideration, my wife Danielle and I know that this is best decision for us," Carlson said in a statement released by the team. "I was blessed to play seven seasons in the NFL for three tremendous organizations — the Cardinals, Vikings and Seahawks. I will always treasure the experiences and relationships made during that time but I'm also very excited about the next phase of my life and what's ahead."

Carlson was on the back end of a two-year, $4.65 million contract he signed in 2014. A second-round pick out of Notre Dame in 2008, Carlson had his best years as a rookie and sophomore with the Seahawks, catching 106 passes for 1,201 yards and 12 touchdowns.

A strong start earned him a five-year $25 million contract with his hometown Vikings before getting cut and signed by the Cardinals. … Carlson did not provide a reason for his early exit, though it's safe to say it came as a surprise. He was working out with the team on Monday.

While it would be unfair to assume any reason for retirement since Carlson didn't give one, it is fair to note this March 2014 Star Tribune story, which makes significant mention of Carlson's concussion problems:

Carlson played 27 games and had 40 catches for 387 yards and one touchdown over two seasons with the Vikings. He finished last season on injured reserve because of a concussion he suffered in Week 14 against the Ravens. It was his third reported concussion in six NFL seasons. Carlson reviewed his health in the offseason with his family, and plans to continue his football career next season.

"It's a serious thing, but I'm not ready to be done," Carson said in February of 2014. "I'm not done, and the doctors are telling me that it's OK that I'm not done."

Whether or not concussions are the reason, he is done now.