Darren Fells

Cardinals TE John Carlson has retired from the NFL.

Carlson, who was going into his eighth year, wasn’t in training camp, but he had been a daily attendee of the Cardinals’ strength and conditioning program and was on the field Monday when the team opened up Phase 2 on-field workouts. In a statement released by the team, Carlson did not indicate a specific reason for his decision.

"After much thought and consideration, my wife Danielle and I know that this is the best decision for us," Carlson said.

Along with Rob Housler's departure via free agency, the Cardinals will be without the two tight ends that played the most in 2014. Darren Fells and 2014 draft pick Troy Niklas sit atop the team's depth chart.