Arizona Cardinals TE John Carlson retires

TEMPE, Ariz. -- Arizona Cardinals tight end John Carlson, whose career was marred by head injuries, retired unexpectedly Tuesday.

In a statement released by the team, Carlson didn't offer a reason for retiring.

"After much thought and consideration, my wife Danielle and I know that this is best decision for us," Carlson said. "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, who will turn 31 on May 12, was entering his second offseason with the Cardinals. He played in all 16 games last season, catching 33 passes for 350 yards and a touchdown. For his career, Carlson caught 210 passes for 2,256 yards and 15 touchdowns.

According to a March 2014 report in the Minneapolis Star Tribune, Carlson suffered three known concussions in the NFL and two additional head injuries while at the University of Notre Dame.

Carlson's 2013 season with the Vikings was cut short after he suffered a concussion in Week 14. He was released on March 5, 2014, and signed a two-year contract with Arizona two days later. He was slated to earn $1 million in 2015 with the potential of another $600,000 through a roster bonus.