"I'm proud of him, regardless of what others may think," the veteran tight end said Wednesday on NFL Network's "NFL Total Access." "I know how hard it is for him, and I know he puts a lot of pressure on himself to be great.
"It's him and Chad Henne," Lewis added. "They're battling, and the way he's just stayed focused, put his head down and pinned his ears back -- I think when it's time to go and the season starts, he'll be ready."
Gabbert enters his third season at a crossroads, fighting with Henne for both his starting job and NFL relevance. The former first-round draft pick's stock has plummeted in two seasons marked by woeful production and injury.
"I think from when Blaine came in and got thrown into the fire once we let David Garrard go. ... It was a tough spot for him to be in," Lewis said. "Because you want to come in and play right away once you get to the NFL, but I think once that really hit him, like, 'OK, this is my time.' It still hit him unexpectedly.
"It's been a little maturity issue there," Lewis went on, "just growing up and owning the offense and taking everybody under your wing and leading us to where we want to go and so far this year from OTAs and quarterback school and being there, he's taken that step forward."