The Rockies experimented with it this year, it appears that they may go with it next season as well. With a 4-man rotation, the Twins can avoid the Liam Hendrickses and the Pedro Hernandezes, and Cole de Vrieses of the world, and it would allow them to go with their 8-man, or even...9-man, bullpen. The starters would be limited to somewhere around 80 pitches a game, instead of 100. With pitchers only facing batters twice, instead of 3 times, it would keep opposing batters off-balance.
A possible Twins 4-man rotation from in-house candidates
2) Samuel Deduno
3) Scott Diamond (had to put a lefty in)
4) Kyle Gibson/Vance Worley/Andrew Albers