Minutes into free agency, free-agent tight end Martellus Bennett announced that he’s going to be a Bear. On his Twitter account, Bennett wrote, “I’m proud to say I’ll be joining my other brother [Brandon Marshall] next season.” He capped it with, “Bear down.” A source said that he’s agreed in principle on a deal with the Bears. The Sun-Times first reported Tuesday the team’s interest in Bennett. Bennett is one of the top free-agent tight ends and would provide the Bears’ offense another weapon.