"Sources" got the earlier non-tender of Daniel Bard correct this afternoon, so even though this is unconfirmed, I'd put pretty good odds on this being correct.
Gamel was claimed on waivers one day short of two months ago from the Brewers. At one time, he was considered a pretty good first-base prospect, but several serious injuries have derailed his career. He hasn't played at all since 2012, and not a full season since 2011. Still, he could provide depth by being the starting first baseman at Iowa, if nothing else.
I'd expect him to be re-signed to a minor-league deal with a non-roster invitation to spring training; I imagine Bard will get the same thing. Theo & Co. appear to be clearing roster space to sign a free agent, although they could also sift through other teams' non-tenders. One man's trash is another man's treasure, as the saying goes. Tommy Hanson, just non-tendered by the Angels, is a possibility; another non-tender that intrigued me from today is Elliot Johnson, who played for the Braves in 2013.Perhaps you saw some names you like in today's non-tenders that the Cubs could try out; leave your thoughts in the comments.
The Cubs' 40-man roster, presuming the Gamel news is correct, now stands at 38.