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."

The Bears announced that they've agreed to a four-year deal with Bennett worth $20 million Tuesday evening.

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.

A second-round pick in 2008, Bennett played behind Cowboys eight-time Pro Bowl tight end Jason Witten in Dallas. After signing a one-year deal with the New York Giants last season, Bennett started all 16 games and finished with 55 catches for 626 yards with five touchdowns. His longest catch was a 33-yard touchdown.

"He's a very good athlete with excellent size," Bears general manager Phil Emery told the team's website. "He's a good receiver who runs good routes."

According to Pro Football Focus, Bennett was rated the NFL's fifth-best overall tight end, ahead of players such as Jimmy Graham (10th), Vernon Davis (9th) and Tony Gonzalez (17th).

As a receiver, Gonzalez was No. 1 and Bennett was 11th. Bennett was ranked 3rd by PFF as a pass blocker and 13th as a run blocker.

Bennett is 6 foot 6, 265 pounds, and he ran the 40-yard dash in 4.68 seconds at the NFL Combine.

If the Bears need salary cap space, releasing tight end Kellen Davis would save $2.5 million.