Spears announced that he's coming to Baltimore on Twitter:
"I'm a raven!! See u in Maryland God is so good"
The Sun reports the deal is worth $3.55 million.
Spears, 30, was cut by the Cowboys this week after spending his entire eight-year career with Dallas, which selected him in the first round of the 2005 draft.
The 6-foot-4, 298-pound end has played in 119 career games, starting 89. Spears has racked up 226 tackles and made 10 sacks in his career.
Last year, he made 25 tackles, including one sack, in 15 games (six starts).
Although he has never made more than 2.5 sacks in a season, Spears is considered strong against the run and should help add depth to the Ravens' defensive front.
Update: The Ravens have officially announced that Spears has agreed in principle on a two-year contract, and the defensive end is expected to be in Baltimore for his physical in the next three days.
General manager Ozzie Newsome issued a statement about his latest acquisition.
"The base of a good defense is to be good along the defensive line," Newsome stated. "We didn't play to our standards last season, partly because of injury. With the expected better health of players like Haloti Ngata and Pernell McPhee and the additions of Marus Spears and Chris Canty, we have a chance to improve. Spears, like Canty, can play multiple positions along the line. He brings a lot of snaps and big game experience to us. We like the way Marcus plays. He will fit in with the Ravens way of playing."