The Winter Meetings end tomorrow with the Rule 5 Draft, where minor leaguers not on the 40-man roster who have spent four years in the minors (or five if they were 18 or younger when first signing) can be taken by any other team. That team can then keep the player as long as they keep him on the active 25-man roster the entire season, of which only half the season can be spent on the disabled list, or they have to spend another entire season on the team's active roster. If the team doesn't keep the player on the 25-man roster all season, he's placed on waivers where any other team can take them, but the same roster requirements apply. If no other team claims him, the player returns to their original team for a nominal fee. Unless their original team doesn't want him back, in which case the drafting team can have him with no roster requirements.
All in all, it's pretty simple.
The Cubs stand to lose a few players this year to the Rule 5 draft. I don't really expect them to take anyone in the draft this season. For one, not counting Taylor Featherston last season, who the Cubs drafted and immediately traded to the Angels. the Cubs have not selected anyone in the Rule 5 draft since Hector Rondon in 2012. Secondly, with the signing of Ben Zobrist and Trevor Cahill as well as the trade for Adam Warren and Brendan Ryan, the Cubs' 40-man roster is currently full. In fact, they're one over when they add Ryan, which is why he was made a "player-to-be-named-later" so that the Cubs would not have to designate someone from their roster and make them eligible for the Rule 5 draft.
On top of all that, the Cubs pick 28th in the Rule 5 draft. It seems unlikely that anyone they might be interested in would still be available when they pick. Even then, the Cubs would have to carry that player on the 25-man roster all season. For a team that had just lost 100 games in 2012, it wasn't a big issue to carry a guy like Rondon. It seems unlikely the 2016 Cubs would be willing to burn a roster spot on a development project.
On the other hand, the Cubs could lose one or more players to other teams. The most likely Cubs prospect to be selected in the Rule 5 draft is right-handed pitcher Corey Black, whom the Cubs acquired from the Yankees for Alfonso Soriano back in 2013. Black throws hard and was the Cubs' No. 16 prospect according to Baseball America coming into last season. But he always had control issues, so the Cubs hoped that a move to the bullpen would help. It didn't, and Black had a terrible 2015 season for the Tennessee Smokies and followed that up with a poor performance in the Arizona Fall League. The Cubs chose not to protect him, but it seems highly likely that some team will take a chance on his fastball. Then it just becomes a matter of whether he can stick on a major league roster all season long next year.
After Black, it's murkier as to whom the Cubs might lose. Right-hander Felix Pena is coming off the best season of his career as a starter for the Double-A Smokies. Pena also throws hard and has also struggled with control, although again, last season he was much better at limiting walks and he struck out more than a batter an inning. I can see a team taking Pena and sticking him in the bullpen for 2016 and then hoping he turns into a back-of-the-rotation starter somewhere down the road. If not, he might be a decent middle-reliever anyway. But from the Cubs' point of view, he turns 26 before Opening Day and still hasn't played above the Southern League.
Those two players are the two that the Cubs are most likely to lose. It is possible that someone takes a chance on left-handed reliever Michael Heesch, who is coming off a good season for High-A Myrtle Beach. Heesch doesn't have overpowering stuff, but his stuff is decent and he shut down left-handers last season to the tune of .191/.267/.265. A team looking for a LOOGY could do worse than giving Heesch a shot.
As far as position players go, the Cubs could lose catcher Taylor Davis, who is an above-average defensive catcher who has hit above .300 the last two seasons at Tennessee and Iowa. Taylor is already 26 and he doesn't hit for much power, but a team looking for decent defense-first backup catcher who can hit at least a little might take a chance on Davis.
Finally, I'd be shocked if outfielders Jeffrey Baez, Kevin Encarnacion or 2B/C Gioskar Amaya were taken in the draft tomorrow because they're just too raw to succeed on the major league level at this point. But you never know. Some team might take them just to get a good scouting report on them, intending to make a trade offer to the Cubs later on. Unlikely, but possible.
So as a prediction, I think the Cubs will lose Black and one other player tomorrow. However, there is a good chance that all players selected off the Cubs roster will be returned next season after failing to make a major league roster. So is this all much ado about nothing? Probably. But then again, someone might turn out to be Hector Rondon for someone someday.