While this is an immediate upgrade to the offensive line, I am not sure it is because Monroe is a stellar player, or the Ravens situation is so completely dire.
Monroe has been an average to above average left tackle since he has entered the league. Monroe had decent seasons in 2011 and 2012. According to Pro Football Focus, Monroe was the the 10th best left tackle in the league in 2012. So, he was in the top third of the league—not exactly top echelon. Plus, there is a reason the Jaguars selected Luke Joeckel with the 2nd overall pick in this year's draft.
Current Raven left tackle Bryant McKinnie must see the writing on the wall with this trade. Pro Football Focus has him rated as the 61st "best" tackle and anybody watching the Ravens' games can see he has greatly struggled in all aspects of the game. Add in the fact that there are now reports of how McKinnie's approach and motivation is less that stellar. He appears to regressing to his 2012 off-season self.
But let's temper this conversation a bit. Monroe is not off to a stellar start to the 2013 season either. He has struggled with run blocking, almost as badly as McKinnie. On the other hand, Monroe is pass blocking at a high level than McKinnie. On some level, at the moment, this is only a bit more than a lateral move for the Ravens.
But in the long run for this season, I think this move serves the Ravens well-especially if Monroe can tap into the success he had in 2012. If so, this is a major upgrade. At 26, Monroe is younger, more athletic, and he has to be more motivated than McKinnie is at this stage in his career. Moving from the worst team in the league, the Jaguars, to a team that has high expectations could be something that re-energizes Monroe. The overall talent on the Ravens and its winning culture could positively help his transition.
The Ravens just may have solved their left tackle problem in the short-run. And, if they re-sign Monroe to a long-term contract, they may solved this issue in the long-run.