Austin Jackson was once a top prospect in the Yankees system, and a top-50 overall prospect as ranked by Baseball Prospectus three straight years, 2008-09-10.
He never played a game for the big-league Yankees. He was sent to the Tigers in the December 2009 three-team deal that shipped Curtis Granderson to New York, Ian Kennedy to the Diamondbacks and Max Scherzer to Detroit, among others. (Other players who later played for the Cubs were in that deal: Phil Coke also went to Detroit and Edwin Jackson wound up in Arizona.) All three teams got value out of the deal; the Yankees got good years from Granderson, the D'backs got helped to the 2011 playoffs with Kennedy and Detroit got several good years out of Scherzer before he departed via free agency.
And then there's Austin Jackson, who was the Tigers' regular center fielder from 2010 until midseason 2014, when he was dealt to the Mariners. From 2010 through 2014 Jackson posted 20.8 bWAR, over 4 bWAR per season. He led the American League in triples twice and was good in center field.
The trade to Seattle seemed to sap all the life out of Jackson's bat. After hitting .277/.342/.413 in 2,994 plate appearances for the Tigers, he hit only .257/.297/.343 with eight homers in 684 PA for the Mariners, which is why they were only too happy to ship him to the Cubs last August. There is, if I am not mistaken, still a PTBNL owed to the Mariners in that deal.
The Cubs need a center fielder, and though they are interested in bringing Dexter Fowler back, if that doesn't work out Jackson could be a good backup plan. As someone who didn't have a great year in his free-agent walk season, Jackson might be available at a reasonable cost for a year as he tries to build up his free-agent value, and the Cubs try to figure out what to do with center field long-term. Jackson plays good defense, can still steal a base (though his percentage was poor in 2015, 17 steals in 27 attempts) and perhaps playing in Wrigley full-time could bring back some of the power he had just a couple of years ago (30 doubles and 12 homers in 129 games in 2013). He's still young enough -- 29 in February -- where this could be a possibility.
Also, have a look at his baseball-reference page. Scroll down to Similarity Scores and check out who his most-comparable player is.
This might be a way to save some money and spend it on pitching, while still having a useful player in center field in 2016.