Tomlin said Bell "perked up dramatically" over the past week. Bell was sidelined for the final two preseason games and first three regular-season games as he dealt with a ligament tear in his right foot.
Quarterback Ben Roethlisberger, however, sounds unconvinced that Bell will hit the ground running.
"Honestly, I have no idea with him," Roethlisberger told KDKA-FM on Tuesday, per the Pittsburgh Post-Gazette. "You can't get a read on him. One day, he's practicing, one day, he's not; one day, he's going hard, the next day, he's not. I wish I could.
"If he was a guy like Heath Miller that you knew was busting his butt every day to get back there," he continued. "Le'Veon is a rookie, I don't know him quite well enough yet. But if he can come back and help us, we'll take him."
The Steelers drafted Bell to be the starter, but he hasn't stayed healthy. He suffered a bruised knee in training camp, then injured his foot after just four preseason carries.
In his final season at Michigan State, Bell carried the load with 382 attempts for 1,793 yards. But Big Ben's comments echo some pre-draft concerns about whether Bell will stay healthy with his bruising running style.
The Steelers' brass believes Bell can be a horse they can ride; however, Bell won't be facing Eastern Michigan, Indiana and Minnesota anymore.