ESPN first reported the deal Tuesday night. The trade won't be official until Monroe, the eighth overall pick in the 2009 draft, passes a physical in Baltimore.
"It was shocking news," Monroe told The Associated Press. "It came out of nowhere for me. I'm just preparing to make the move. It's a fresh start."
Monroe has started 62 games over five seasons, including the team's past 30 games. He was Jacksonville's best offensive linemen this season, getting beat at times as he tried to pick up the slack for struggling guard Will Rackley.
With Monroe in the final year of his contract and the winless Jaguars clearly in the early phases of a complete rebuilding project, it made sense to trade him now and get something in return.
ESPN reported that the Jaguars would receive multiple third-day picks for Monroe in the 2014 draft.
Jacksonville will move second overall pick Luke Joeckel, who started the first four games at right tackle, to the left side.
Monroe could replace Ravens left tackle Bryant McKinnie, who has struggled this season. If he does break the starting lineup and plays well, it could mean a long-term deal for the former Virginia standout and Plainfield, N.J., native.
"I hope it works out," said Monroe, whose wife is from the Baltimore area.
The Ravens hope Monroe can help an inconsistent line that has had difficulty opening holes for running backs Ray Rice and Bernard Pierce. Baltimore allowed four sacks last Sunday in a 23-20 loss to Buffalo.
McKinnie started for Baltimore in the Super Bowl and was re-signed as a free agent late in the offseason.
Ravens coach John Harbaugh didn't single out McKinnie as the problem behind the team's lackluster running game, but it was apparent that something had to be done after Baltimore set a franchise record for fewest rushing attempts against Buffalo (nine). Baltimore also is 28th in the league in rushing, averaging 64 yards a game.
"I think the whole O-line is disappointing right now," Harbaugh said Monday. "There's no one more disappointed than they are right now. We've got to run block better, we've got to pass block better."
The question now in Jacksonville: who's next? With Monroe gone, the team has just one player on the roster (defensive end Tyson Alualu) from any of the three drafts between 2008 and 2010.
And it's clear the Jaguars aren't even close to being competitive, so why not try to trade guys with value who aren't in general manager Dave Caldwell's long-term plans?
The players could include running back Maurice Jones-Drew, tight end Marcedes Lewis or linebacker Paul Posluszny.
AP NFL website: www.pro32.ap.org