There's been no official announcement from the Cubs, but according to Baseball America the Cubs have signed free-agent outfielder Adron Chambers to a minor-league contract. This will likely include a non-roster invitation to spring training.
Chambers is 28 and played parts of three seasons (2011-13) with the Cardinals, mostly as a pinch-runner and defensive replacement. His minor-league record shows some nothing-special offense (though with a good .364 OBP) and good defensive statistics. He spent 2014 split between the Triple-A affiliates in the Astros and Blue Jays organizations.
This signing is likely for nothing more than organizational outfield depth; Chambers is the kind of guy who gets called up briefly as an injury replacement or added to the roster in September the way the Cardinals used him, as a defensive replacement or pinch-runner.
Chambers has actually done pretty well for someone drafted in the 38th round (2007) out of a junior college (Pensacola Junior College in Florida). Most guys selected that low never even sniff the cups of coffee that Chambers has had. As noted, though nothing's official yet, I'd expect him to receive a NRI to major-league spring training.