Weeden sustained a concussion in the closing minutes of Sunday's 20-14 win over Pittsburgh, just Cleveland's second against its biggest rival in 18 games. Weeden was falling following an incompletion when his head struck the leg of teammate Joe Thomas.
The 29-year-old left the field and received medical attention on the sideline before he was taken to the locker room. He was replaced for two series by backup Colt McCoy, who will start against the Raiders if Weeden isn't cleared.
Browns coach Pat Shurmur said Weeden was at the team's facility on Monday. He is being treated under the NFL's "strict concussion protocol" and his status for Sunday's game remains uncertain.
"We'll go through the process and we'll know way more on Wednesday," said Shurmur, who would not speculate if Weeden will face the Raiders. "I'm not making any predictions at this point."
Shurmur would not comment when asked if Weeden did any physical activity. Typically, players are prohibited from exercising on the first day after a concussion is diagnosed and encouraged to rest. It's not known if Weeden sustained a serious head injury. He didn't appear to take a hard hit, but that's not always a definitive indicator of an injury's severity.
The Browns are ultra-sensitive to head injuries and their treatment. Last season, the mishandling of McCoy's concussion against the Steelers prompted the league to make changes in its policies on concussion examinations. There is a now a certified athletic trainer at games to monitor play and provide medical staffs with information to assist their treatment of injured players.
Shurmur knew Weeden wanted to stay in the game and close out the win. Browns rookie running back Trent Richardson said trainers had to hide the QB's helmet so he couldn't re-enter.
"I don't think anybody wants to leave the game," Shurmur said. "Especially a game that's in the balance like that one was. So I think that's typical of what I see and feel from guys that are on the sideline. Of course, we know there's protocol. We're well aware of that, right?"
Weeden finished 17 of 26 for 158 yards with one touchdown and an interception on a pass that was tipped at the line and returned 53 yards for a touchdown by Steelers linebacker Lawrence Timmons just 1:11 into the game.
Shurmur gave a somewhat mixed review on Weeden's outing.
"He did some good things in that football game," Shurmur said. "But as we move forward and get ready to play the Raiders, there's some things that he can clean up that'll help us have a better performance next week."
McCoy went 4-9 in 13 starts last season before he was injured. The three-year veteran, who was thrust into a starting role for eight games as a rookie because of injuries, had assumed he would start this season. However, he lost his job when the Browns drafted Weeden in the first round of April's draft.
Shurmur is confident McCoy can step in and perform well if he's called upon to play.
"If Colt goes in the game, I expect he's going to function fine and help us win games," Shurmur said. "I have all the confidence in the world in Colt. Colt has handled his situation this year in a very professional way. I don't see any reason why he can't go in and function well."