49ers waive Clayton; sign new FB

The knee injury suffered by running back Thomas Clayton during Friday’s exhibition opener against the Denver Broncos has ended his season and temporarily ended his stay on the 49ers’ roster.

With Clayton facing season-ending surgery after tearing the anterior cruciate ligament in his right knee, the 49ers opted to waive the third-year veteran Sunday.

Any other NFL team can now claim Clayton, who was beginning to attract some attention around the league. But that seems unlikely to happen now that he’s out for the season.

If he goes unclaimed, Clayton automatically reverts back to the 49ers and will go on injured reserve. If the 49ers had just placed Clayton on injured reserve without the "waived" designation, he still would have counted against the team's 80-man limit until the first roster cutdown day on Sept. 5.

Clayton, the team’s sixth-round draft pick in 2007, spent his first two seasons with the 49ers on the team’s practice squad before being elevated to the 53-man roster last December after several other teams displayed interest in him. He did not play in any of the three games he was on the roster.

“It’s always unfortunate when you lose anyone that’s trying to make a football team," 49ers coach Mike Singletary said. "He’s just a guy that really works hard. He gives you everything that he has on every down and we know that he had high hopes of being part of the team. When you look at him, he’s the kind of guy that everything that he’s doing you know that he’s going as fast as he can go, he’s going as hard as he can go and he’s just one of those guys that when you look on him on film, you know that you’re going to get everything that he has on every play. Every team is looking for somebody that will do that.

"When someone like that goes down, it’s always a difficult thing to see. So, we’ll just have to rehabilitate the knee and go from there.”

After the addition of third-round pick Glen Coffee this year, Clayton was going to be hard-pressed to make the roster, but he definitely was in the running for a backup role behind starter Frank Gore. And another strong preseason could have landed him on another roster if he did not find a place with the 49ers.

That all changed in the fourth quarter Friday when Clayton took a first-down handoff and looked for an opening up the middle. While attempting to cut, Clayton was hit from the side by a Denver defender and landed awkwardly on his knee.

He immediately went down in pain and was on the turf several minutes before being taken off the field on a cart.

Clayton was a hard-working individual with the 49ers who led the NFL with 200 yards rushing during the preseason in his rookie season and also led the 49ers in that department last preseason. In eight exhibition games over the past two summers, Clayton rushed for 386 yards on 87 carries (4.4 average).

But he never could crack the final roster heading into either season, and this year probably was going to be his final shot at sticking with the team. If Clayton clears waivers, the 49ers will then have the option of bringing him back next season.

To replace Clayton on the team’s training camp roster, the 49ers on Sunday signed rookie fullback Bill Rentmeester, who played last year at the University of Wisconsin.

The 6-foot, 254-pound Rentmeester was originally signed as an undrafted rookie free agent in May by the San Diego Chargers. He was released by the Chargers on Aug. 5 after beginning training camp with them.

Rentmeester will fill in for injured fullback Zak Keasey, who is expected to miss 8 to 10 weeks with a broken forearm suffered in the Denver game. The 49ers did not make any roster move with Keasey, leaving open the possibility of carrying him on their 53-man roster to open the season.

Clayton’s departure could open the way for rookie Kory Sheets to have a shot at the final roster if the 49ers decide to keep six running backs.

Sheets was impressive running the football late in the game against the Broncos, gaining 51 yards on 10 carries while ripping off runs of 25 and 13 yards on San Francisco’s final possession.

But he also miffed coaches by going out of bounds at the end of his 25-yarder instead of remaining in bounds as the 49ers were attempting to run out the clock in the final minutes.