One of the hallmarks of a winning team, and there are many, is that they have depth. Having players who can put up four or five-win seasons is a big measure of success, but so is having a limited number of players who are essentially replacement level (or worse.) This is the area where the Twins have been the most successful this winter: raising the floor.
The best evidence is in the fact that Trevor May, Alex Meyer and Tommy Milone will be fighting for the last spot in the rotation, but you could also point to the bench; Josmil Pinto as the backup catcher; Eduardo Escobar as the backup infielder. All five of the aforementioned players should be able to create positive value.
But there's another level to raising the floor, which is providing the team with players who can step into roles and tread water. To some extent maybe the Twins can rely upon Miguel Sano or Eddie Rosario or any of a trio of relievers or even one or both of May and Meyer, but Minnesota clearly won't (and shouldn't) rely on these players earlier than their development dictates. This is why adding veterans on minor league contracts is such a good insurance policy.
Blaine Boyer is an example of this philosophy, as is the addition of Shane Robinson. Both players have Major League experience, neither player is on the 40-man roster, and if the Twins find themselves in a scenario where they need someone to just soak up 40 innings or 200 plate appearances the team could do worse. I think you'll agree that in the last three or four years, when it came to these situations the Twins really couldn't have done worse.
With those things in mind, who is still available on the free agent market that the Twins could tempt into a minor league or split contract?
Age: 31 | Pos: OF
Between 2008 and 2013, Schierholtz averaged 1.0 fWAR. His 2014 wasn't as impressive, seeing him post the first negative fWAR of his career, but for the defensive value he provides in the corner outfield he could conceivably be a a guy whose bounce back season nets him positive value. He's a career .253/.302/.405 hitter, so he's as unlikely a hero as Jordan Schafer, but the goal of this exercise is to find players who could be amenable to a minor league deal while also being a fair bet to provide better than replacement-level value. Schierholtz fits that description to a T.
Age: 33 | Pos: RHP
Crain was a sunk cost for the Astros in 2014, missing the entire season and eventually having Tommy John surgery. Still, all he did from 2011 through 2013 for the White Sox was strike out 29% of batters faced with a 2.10 ERA. It's a bit of a gamble, because he won't be available to pitch until the season is underway, but if the organization is still obsessed with reunion tours and wants a low-risk, high-reward opportunity, Crain is certainly an interesting option. As far as I'm aware, his market has been non-existent.
Age: 35 | Pos: 2B/3B/SS
Since becoming a utility player for the Tigers in 2008, Santiago has hit .249/.324/.343 with the ability to play all three infield positions adequately. In that time span he's also accumulated 4.9 fWAR, consistently posting positive value even if it's less than 1.0 fWAR per season. The Twins have Doug Bernier, James Beresford, Argenis Diaz, and Jose Martinez for their infield in 2015, however, so adding an infielder like Santiago would depend on how confident the organization would be in the ability of any of those players to be at least as good as Santiago could be.
Age: 34 | Pos: C
Baker bats left-handed, which makes him an interesting alternative to both catchers on the 40-man roster as well as both of Rochester's receivers: Eric Fryer and Dan Rohlfing. He's rarely played enough to accumulate any kind of value, but in 359 career games is worth 1.5 fWAR and is the owner of a solid defensive reputation. By pitch framing standards he's more or less average. I have a hard time seeing the Twins throwing another non-40-man catcher into the mix, but if they really want that left-handed guy...
Age: 36 | Pos: LHP
An update since I've tweeted about him enough the last few weeks: #MNTwins expected to watch Johan pitch today. Saw him last week too.— Darren Wolfson (@DarrenWolfson) January 13, 2015
Injuries have derailed Santana's now star-crossed career, but he's not giving up and it on a program to get him back on the mound. The Twins have repeatedly been noted for their interest in their former ace, and there's literally zero risk involved in this kind of a move, so it's as simple as this: do the Twins think there's any chance of Santana working his way back into a position where he could pitch to Major League hitters? If not: is it worth the gamble to give him a minor league offer? Regardless of your answer, Johan is probably the outlier on this list as he's the least likely to even be capable of putting on the uniform.
Those five players would all be good additions for depth, and I'm fairly certain that they would all at least listen to a minor league offer. These players would likely ask for an opt-out if they're not on the roster by a certain date, but that's fine. If they don't, A) depth is good, which we know, and B) there's nothing wrong with having Major League experience at Triple-A for the younger guys who will be sifting through.
Maybe you could convince a guy like Carlos Villanueva to sign a split contract, but I'm dubious. Is there anyone else you think the Twins could have a shot at netting on a minor league deal? You can see MLBTR's full list of free agents here.