The Cubs will be looking to upgrade their defense this season and one place to do it is in the OF. Now that's currently where Alfonso Soriano resides and there's the problem of 3 yrs and $54M to deal with.
The free agent crop for OF'ers is rather thin. Two of the top names, Michael Cuddyer and Josh Willingham, aren't a whole lot better on defense than Soriano is. There are two candidates, however, that could upgrade that LF play. The first is Grady Sizemore and the second is David DeJesus.
Sizemore is the bigger risk of the two. He also presents the bigger potential reward. He had a microfracture in his knee, similar to Carlos Beltran, and he hasn't played well now for two seasons. For the Cubs, though, that may provide an opportunity to approach him about a short term, make-good contract.
Sizemore's days as a 5 tool centerfielder are probably behind him. A move to LF is probably a good idea at this point so that he doesn't have to cover as much ground and put more wear and tear on the knee. He has also simply lost a step, and while he cannot be a top shelf CF'er, it's reasonable to expect him to play well enough in LF.
At the plate, Sizemore inexplicably lost all semblance of patience. His walk rate was at just 6% as opposed to about 11% in his career before 2011. His ISO power was a respectable .198, down about 6 points from his career average, but close enough to where it's reasonable that he could rebound in that area. The hope is that you get a guy who can play a solid LF, get on base, and hit for some power. That would make him an upgrade over Soriano.
Another, less risky option, is David DeJesus. DeJesus is an outstanding defensive corner outfielder and, while he had an off year at the plate, he's a career .284/.356/.421 hitter. The slugging would represent a dropoff from Soriano, but DeJesus is better in every other category. It's a tradeoff that makes sense for the Cubs. What little they lose in offensive production, they more than make up for on defense and OBP skills. To use a more all encompassing measure, DeJesus actually had a higher WAR than Soriano (2.2 vs. 1.3) despite his worst offensive season in years.
Either player would upgrade LF on defense without much of a dropoff on offense. Neither is expected to be all that expensive. Sizemore may be willing to sign a make good, incentive laden contract while DeJesus is coming off an off year. Either could be the last piece on the makings of a good defensive outfield with Jackson and Byrd.
Of course, the Cubs will have decide what to do with Soriano's big contract first.