Tomlin told reporters Tuesday that Bell's performance level needs to improve "and it will," per ESPN.com's Jeremy Fowler.
Bell ran for 32 yards on 10 carries, which are tied for his fourth-fewest rushing yards in a single game, and he caught three passes for 15 yards.
The 2016 Pro Bowler missed almost all of the preseason before he officially signed his one-year franchise tender for the Steelers, which led some to question whether that was the reason he struggled to get going against Cleveland.
Bell addressed the story on Twitter:
Tomlin said Tuesday he had already moved on.
"You can sing that Le'Veon Bell camp song all you want," he said. "He's here. We're working. It's Week 2. We're getting ready to play the Minnesota Vikings. I'm done with it."
Things won't get much easier for Bell with the Steelers welcoming in the Minnesota Vikings on Sunday. The Vikings ranked eighth in defensive efficiency last year, according to Football Outsiders, and they held the trio of Adrian Peterson, Mark Ingram and Alvin Kamara to 53 yards on 19 carries in their 29-19 win over the New Orleans Saints.