His ability to play all over the field (potentially even at first base) will give Joe Girardi a lot of options this year.
After bringing in Jacoby Ellsbury and Carlos Beltran to join Brett Gardner in the outfield, Alfonso Soriano will probably begin 2014 as the team's designated hitter. Soriano hit 34 home runs with a 112 wRC+ last season, so finding a way to keep his bat in the lineup is a smart move, and if he can replicate these numbers - or get somewhere close - the Yankees will have quite a heart of the order with him, Carlos Beltran, Mark Teixeira, and Brian McCann.
While his bat is what makes Soriano so valuable, his versatility might be the key to keeping that bat in the lineup. With an aging roster that has a number of players trying to rebound from injury, Joe Girardi will no doubt look to give Derek Jeter, Beltran, and Teixeira some games in the DH spot. Soriano probably won't be starting at shortstop any time soon but he can play multiple positions in the outfield, and has even worked out at first some this spring. This means that when Beltran needs a game off and Girardi wants him to DH, Soriano should be a perfectly serviceable replacement in right. Even though Soriano has primarily played left field in the past few seasons - where he's been an above average fielder - his speed and outfield experience should allow him to transition well to right field (he's even played there some this spring) while making sure his bat stays in the lineup.
Soriano will also provide some (albeit slight) insurance in case of a Jacoby Ellsbury injury. While an extended stay on the DL will seriously endanger Yankee playoff chances, if Ellsbury experiences some minor injuries (like the tightness in his calf that has been bothering him for the past week or so) Soriano's ability to take over in left while Brett Gardner shifts to center will allow the Yankees to still field a good outfield, both defensively and offensively. This shouldn't do too much damage to them in the short term (although again, a long-term injury to Ellsbury will be a tough blow to recover from). Shifting Soriano to the outfield in this scenario would leave a large hole at the DH spot (a hole that could be filled by Ichiro Suzuki or, gasp, Eduardo Nunez), a lineup with Ichiro and Soriano is still a lot better than the 2013 lineups that included both Ichiro and Vernon Wells.
As mentioned above, Girardi has even had Soriano work out at first and has alluded to him playing some there during the regular season. Girardi, when asked about the possibility, said, "I think he's athletic enough to do it. He's played that side of the infield before." With Teixeira recovering from injury and no real backup (except for starting third baseman Kelly Johnson) on the roster, Soriano looks to be a potential backup at first base. Caitlin has even floated this idea here at PSA. If he can manage it defensively, it will allow Teixeira some games at DH while keeping Soriano's dangerous bat in the lineup.
Since Soriano is one of the only right-handed hitters the Yankees have, and one of the team's main power threats, having his bat in the order makes the Yankees undoubtedly better. His versatility will let Girardi swap DHs out over the course of a long season, which will give Teixeira and Beltran the rest they need without sacrificing any of the offensive firepower that the Yankees will need to truly contend in 2014.