"I don't see any circumstances where Ben does not finish his career here," Colbert told reporters Monday, per the Pittsburgh Post-Gazette.
Team president Art Rooney II explained last week that the Steelers told Roethlisberger they won't extend his contract until after the 2014 season.
Big Ben has two years remaining on the eight-year, $102 million contract he signed in 2008. He will make $12.1 million this season with a nearly $19 million cap hit.
The quarterback has spoken positively about his team -- especially the offense -- this offseason, but eventually he wants to get paid along the lines of other top quarterbacks.
"Playing this year at my current salary, it's kind of taking a hometown discount," Roethlisberger told the Pittsburgh Tribune-Review. "I've played seven years on my current contract, which is the most of any (NFL) player or any quarterback. ... It is kind of taking a discount compared to maybe where it could be compared to other quarterbacks."
While the situation sometimes seemed gloomy last year, an extension keeping Big Ben in Pittsburgh now seems to be a matter of when, not if it will get done.