Clayton was signed on Tuesday and replaced Brian Robiskie on the active roster. Ogbonnaya was signed off the Texans' practice squad two weeks ago and has accounted for 119 yards in the two games. Last week, he carried the ball 11 times for 37 yards and caught five passes for 24 yards.
"We just have to see how much (Hillis) can do and see if he can get himself into position to play," Browns head coach Pat Shurmur said. "He'll be out there and we'll just see. It's hard to tell until we see."
Shurmur said Hillis was at Wednesday's morning walk through, but he was not on the field in the portion of practice available to the media.
This week's opponent, the Houston Texans, know all about hamstrings. Houston's leading rusher, Arian Foster, missed the two of the first three games because of a hamstring. He has bounced back to rush for 532 yards and four touchdowns, to go along with 22 receptions for 317 yards and a touchdown. Last week, Foster had 112 yards on 33 carries with a touchdown and caught one pass for 12 yards.
Besides having one of the premier running backs in the NFL, the Texans have a very good backup in Ben Tate, who has 508 yards and a touchdown.
Shurmur was asked if Hillis is letting the team down and he side-stepped the question.
"In terms of guys coming back from injury, you just hope they can play."
If Ogbonnaya and Clayton carry the load, combined the duo have just 23 carries in NFL games.
Clayton was drafted by the 49ers in the sixth-round of the 2007 NFL Draft and spent three years in San Francisco. In 2010, Clayton was on the Browns' active roster for two weeks and the practice squad for four weeks. He was on the Patriots' active roster for nine weeks. He was with the Seahawks for 2011 training camp.
Shurmur is hopeful that Clayton (5-foot-11, 220 pounds) will be able to contribute against the Texans, if needed. Clayton, who is wearing number 33, has just six NFL carries for 17 yards - all with the Patriots.
"Obie (Chris Ogbonnaya) did it in three days," Shurmur said. "If he's in there, we expect him to play."
Massaquoi, Gocong Hopeful: Wide receiver Mohamed Massaquoi (concussion) and linebacker Chris Gocong (stinger) are hopeful to play this week. Gocong was back at practice and Massaquoi was at Wednesday morning's walkthrough, but wasn't on the field Wednesday afternoon during the time available to the media. Meanwhile, defensive lineman Auston English (knee) and Hardesty (calf) were ruled out for this week's game.
"(Massaquoi) was at the walk through and we'll see what he can do," Shurmur said.
Defensive back Dimtri Patterson (knee) was limited and if he can't play, defensive back Buster Skrine would step into the third cornerback role.
Defensive back Ray Ventrone (hamstring) was back at practice.
Big Andre: There's a possibility that Texans wide receiver Andre Johnson will return Sunday after missing several games after having surgery on his hamstring.
"When he's in the game they try to get him the ball," Shurmur said. "He's one of the most explosive receivers in the league."
There's a good chance that Joe Haden will draw the assignment of covering Johnson.
"(Joe's) had an outstanding first half of the season and has come back from injury," Shurmur said.
Shurmur stopped short of saying Haden would cover Johnson regardless of the side he lined up on.
"If Andre Johnson is out there, Joe Haden probably won't be far away," he said.
Hardesty Timetable: Shurmur doesn't know how long Hardesty will be out. The estimated timetable for a torn calf muscle is two to four weeks.
"It's hard to say," Shurmur said. "Guys heal at different rates. I feel bad for Montario as he's worked hard to get back."
So Long, Brian: Shurmur said it was a tough decision to release wide receiver Brian Robiskie, but said the team needed another running back.
"This is the time you have to make roster moves," Shurmur said. "I like Brian, but based on the way the roster was we had to make a move. I wish him the best and hopefully, he'll get another chance."
Robiskie was drafted in the second-round (36th overall) by Eric Mangini in the 2009 NFL Draft. Robiskie had just 39 catches in three seasons. Robiskie caught just three passes for 25 yards in 2011, starting the first four games.
Shurmur was asked what went wrong with Robiskie.
"I'm not sure," he said. "He competed and was given his opportunity to play."
Currently, the Browns have just five receivers.
Why No Veteran WRs: Shurmur was asked why the Browns didn't bring in a veteran wide receiver like T.J. Houshmandzeh or Brandon Lloyd.
"We're always looking for any and all players to improve the team," he said. "My job is to get the team better. (Tom Heckert and I) go through and talk about everybody that's available and try to make decisions that are best for our team."