Roethlisberger missed Wednesday and Thursday practices with a right elbow bruise, and the team listed him as questionable on Friday's injury report.
"Obviously, him throwing the ball first day back, he was taking it slow and getting back into it, but eventually it's game day, it's game time," wide receiver JuJu Smith-Schuster said. "He's going to be out there playing with your boys. I think that's what he's going to do."
Coach Mike Tomlin confirmed Roethlisberger practiced but declined to comment on details, deferring to the injury report. Roethlisberger declined comment as he left the locker room.
Backup Josh Dobbs, who took first-team reps Wednesday and Thursday, said he returned to his normal workload in light of Roethlisberger's participation and has not been told he's starting. "I will be ready if my number is called," he said.
Asked if he saw Roethlisberger handing the ball off with his left hand Friday, center Maurkice Pouncey said he's seen Roethlisberger do all kinds of impressive things over the years.
"He looked really good," Pouncey said. "No matter if he's at practice or not, you know how tough he is and the things he plays through. He's motivated to get back out there."
Pouncey said he "always" expects Roethlisberger to play unless he takes the field Sunday without him.
Another offensive starter told ESPN he has no doubt that Roethlisberger will play. And Antonio Brown had his unique twist on Roethlisberger toughing out injuries, saying his quarterback is "exceptionalism. He's not ordinary. He's extra-ordinary. ... He's not bound by how he feels. He's not bound by where he comes from. He's a difference maker."
After a five-turnover performance in Week 1 against Cleveland -- including three interceptions and two sack-fumbles -- Roethlisberger is eager to rebound.
The Steelers have won six of their past seven games against Kansas City, including a 43-14 win on Oct. 2, 2016, at Heinz Field that featured a five-touchdown performance from Roethlisberger.
"I tell you what, that's last week," said Roethlisberger on Wednesday. "We can look at it, but you've got to move on, because you've got a game this week. We did our film study on Sunday and Monday, and now we're moving on to Kansas City. We've got to focus on that."
While expectations are that Roethlisberger will play, guard David DeCastro (hand), cornerback Joe Haden (hamstring) and defensive end Tyson Alualu (shoulder) are all listed as doubtful for Sunday's game.