Thomas, the third overall selection in last year's draft, started all 16 games for the Browns and was part of an offensive line that allowed only 19 sacks, the third-fewest in franchise history.
"I am thrilled to be selected for the Pro Bowl and for the opportunity to play with some of the best players in the NFL," said Thomas. "I understand that being selected as an alternate means that someone else could not attend, so I wish the best for Jason Peters. But this is truly an honor and I will do my best to represent the Browns and the AFC in Hawaii."
Information from The Associated Press was used in this report