Trent Richardson's professional football career is hanging by a thread, and he's not off to a good start with his fourth NFL team in as many years. Baltimore Ravens head coach John Harbaugh said the former third-overall draft pick is still struggling with his conditioning.

"Trent just needs to get healthy," Harbaugh said, per ESPN's Jamison Hensley. "I think the workload and the amount of work it takes to be a world-class conditioned athlete is something that he's working on right now. That's what he needs to understand, and that's where he needs to get himself."

Harbaugh said he won't be able to evaluate Richardson until he's in shape, per ESPN, and that may never happen quite frankly.

Richardson was a standout at Alabama and carried some of that success over into his rookie season with the Cleveland Browns (1,317 yards from scrimmage, 12 total touchdowns), but he was traded to the Indianapolis Colts during his second season. He was not very effective with the Colts and was waived after the 2014 season.

The Oakland Raiders signed Richardson to a two-year, $3.85 million contract last offseason, but he didn't even make the team. His last chance to save his NFL career is likely with the Ravens this year.