The Miami Dolphins are working out free-agent quarterbacks Rex Grossman, John Skelton and Brady Quinn on Monday, according to NFL.com.

Matt Moore (shoulder) and Pat Devlin (hamstring) returned to practice from injuries on Sunday, but the Miami Herald reported that the team is not comfortable with the backup quarterback situation behind starter Ryan Tannehill.

Moore played in one game for the Dolphins last season, completing 2 of 6 passes for 53 yards. Devlin has not played in an NFL game.

"We've had workouts almost every single day and it's no different," coach Joe Philbin said Monday when asked about bringing in veteran quarterbacks. "We're always evaluating different people that are out there. So really, no different than any other position. We've brought in people at virtually every position."

Grossman spent the past four seasons with the Washington Redskins but has not thrown a regular-season pass since 2011.

Skelton could not stick with a team last year after spending three seasons with the Arizona Cardinals, including 17 starts.

Quinn has a television deal in place with Fox Sports in case he does not latch onto a team. He also recently tried out with the New England Patriots.

Philbin was asked whether Moore would be the backup quarterback this season.

"Well, we're really not at that stage where we're going to decide who the final 53 players are," Philbin said. "That won't come, we're probably two-and-a-half or so weeks away. When that time comes, we'll know. We really haven't named anybody anything. We haven't anointed, this player, that position. We're still in a competitive mode. We want to get an opportunity to evaluate a lot of different players at different spots and that's still going to continue, certainly for sure this week."

Philbin also gave his assessment of Devlin and whether there has been improvement in his development.

"Well, I can only speak to when I got here. I know he was here a little bit before me. But, yeah, I like (him). I think he's definitely developed," Philbin said. "I like his play speed. That's one of the great strengths that I think he has. He plays the game fast, he's decisive when he's back there. But again, let's call it what it is, and he has to be out there on a more consistent basis to get a good, thorough evaluation."

Also on Monday, the Dolphins signed running back Cameron Marshall and waived quarterback Brock Jensen.

The 5-foot-9, 217-pound Marshall re-joins the Dolphins after being waived by the team on May 28. He originally signed with Miami as an undrafted rookie free agent in May 2013 out of Arizona State.

Jensen led North Dakota State to three consecutive Division I FCS national titles. The Dolphins signed him as an undrafted rookie free agent this summer.