Free agent officially kicks off at 4 p.m. Tuesday, so let's take a look at the three biggest needs for the Ravens:
1. Interior offensive line: Left guard Ben Grubbs will likely sign elsewhere in free agency, and starting center Matt Birk and backup Andre Gurode are also unrestricted free agents. This is by far the biggest void on the team. The Ravens are expected to bring back Birk and draft their center-in-waiting next month (Wisconsin's Peter Konz is the favorite). But general manager Ozzie Newsome likes to fill major needs before the draft. If Baltimore adds a guard, its track record suggests a veteran one like Steve Hutchinson or Bobbie Williams.
2. Outside linebacker: The Ravens could have trouble re-signing Jarret Johnson, which makes this position a bigger need than many project. Baltimore drafted Sergio Kindle in 2010 to eventually take over for Johnson. But a fractured skull when he fell down two flights of stairs before training camp has made him a non-factor. The Ravens could try to use Paul Kruger at outside linebacker, but he isn't as physical as Johnson in setting the edge against the run. The Bengals' Manny Lawson and the Seahawks' Leroy Hill stand out in a weak free-agent group for outside linebackers.
3. Wide receiver: Baltimore has failed to find a dependable No. 3 wide receiver for Joe Flacco, striking out with T.J. Houshmandzadeh in 2010, and Lee Evans in 2011. The Ravens have ruled out going after a top-tier wide receiver, so that presumably takes them out of the running for Reggie Wayne. But they need to add more punch to a wide receiver group that had two players with more than four receptions last season (Anquan Boldin and Torrey Smith). The Broncos' Eddie Royal would be a solid addition, because he would fill the role as the No. 3 wide receiver and punt returner (the team would probably like to reduce Lardarius Webb's snaps on special teams). Royal's receptions have dropped off heavily since his 91-catch rookie year in 2008, but that happened to be his final season with quarterback Jay Cutler.