After three years, Josh Freeman is a team captain no more. According to Pat Yasinskas, this year's team captains are Dashon Goldson and Gerald McCoy on defense, Vincent Jackson and Davin Joseph on offense and Adam Hayward on special teams.
I wouldn't worry too much about Freeman not being selected a team captain. The quarterback position has a natural leadership role, captain patch or no. It's been clear throughout the offseason that Freeman does not have the complete confidence of the team, either, although he was never in danger of losing his starting job. He just has to answer a few questions this offseason.
If you do want to give some extra weight to the big C on the chest, then the fact that Freeman was a captain for three years is probably more significant than the fact that he isn't anymore. This may be more about Davin Joseph and Vincent Jackson than Josh Freeman. Or maybe it does suggest a shift in team dynamics this season.
Another shock would be the selection of Dashon Goldson as a team captain. We've heard about his leadership throughout the offseason, but he's still a free agent coming in from another team. Having your prime free agent be named a team captain is always encouraging, though.
We don't actually know how the captains are selected. Usually, player votes determine that, but then there are always rumors that those votes are rigged by the coaches and front office.