Raiders admit they were blindsided by decision this player made just before the start of training camp

The Las Vegas Raiders got a huge surprise at the start of training camp on Tuesday when Michael Gallup decided to announce his retirement after just six NFL seasons.

During an interview this week, Raiders general manager Tom Telesco admitted that the receiver's decision caught the team totally off-guard.

"I didn't see that one coming at all," Telesco said, via The Athletic .

Gallup signed with the Raiders on April 30 , which means he had been with the team for less than three months before making the decision to call it quits.

"That just kind of came up out of the blue," Telesco said of the retirement. "When I talked to him, it seemed like he had a pretty clear vision. He's ready to move on. It's too bad."

The Raiders were clearly given no indication that Gallup might be thinking about retirement. The receiver showed up for OTAs and minicamp during the spring, so the team obviously expected him to show up for training camp.

Gallup was cut by the Cowboys in March, but he's only 28 years old, so the Raiders figured that he still had plenty left in the tank. The veteran finished with at least 400 yards and 30 receptions in each of the past three seasons in Dallas and he likely would have made the roster in Las Vegas.

It's been three days since his retirement announcement and Gallup still hasn't explained why he decided to call it quits, and until he decides to talk, it looks like his reason will remain a mystery to all, including the Raiders.