Oakland Raiders head coach Jon Gruden says he's "surprised" that free agent quarterback Colin Kaepernick remains unsigned. Gruden's comments about Kaepernick came during the coaches breakfast at the NFL owners meetings on Tuesday.

In speaking about Kaepernick, Gruden brought up the names of some other well known QBs who have been out of the league for some time, including Johnny Manziel, Tim Tebow and Robert Griffin III.

"I think there's a lot of intrigue there," Gruden said Tuesday at the coaches breakfast at the NFL owners meetings, according to ESPN. "His performance on the field wasn't very good, on tape. I think, Robert Griffin, a rookie of the year, [I'm] surprised he's out there. Tim Tebow takes a team to the playoffs, there's some surprise that he never came back. You know, Johnny Manziel, he's out there.

"Back to Kaepernick, he got beat out by Gabbert to start the [2016] season. I think that says something. [But] I am surprised he's not in camp with somebody. He probably will be soon."

Kaepernick was actually recovering from three surgeries when Blaine Gabbert beat him out for the starting job in 2016, but he reclaimed the position once healthy. He finished with a 90.7 passer rating, completing 59% of his passes for 16 touchdowns and four interceptions, but has not played in the NFL since that 2016 season. Gabbert, a former first–round pick, signed a deal with the Tennessee Titans today.

Kaepernick filed a grievance last October against NFL owners for collusion, claiming they schemed to keep him off the football field because of his protests.