The Yankees need a new lefty in the bullpen now that Boone Logan is a free agent and might not re-sign. The Yankees have some internal options, like Cesar Cabral and Francisco Rondon, but nothing substantially overwhelming to win the job. Unfortunately, while Eric O'Flaherty would make a great replacement, he won't be an option for the 2014 Yankees. In 2013 he underwent Tommy John surgery in May and will likely miss the entire season.
Still, it might be worth investing some money into him in order to retain his services for the future. He'll be 30 in 2015, with a career 2.85 ERA and 3.44 FIP. His 6.91 K/9 and 3.13 BB/9 aren't the greatest, but against lefties he had a 2.89 FIP, a 7.43 K/9 and a 2.09 BB/9. Of the free agents that are available now and could be available next season, O'Flaherty has the best ERA against lefties (0.98), the lowest walk rate (1.71) and HR/9 (0.24), and the third lowest FIP (2.30). He also actually has the lowest ERA (2.11) and second lowest FIP (3.56) against righties. That's how good he has been and how good a signing he would have been.
The Yankees should probably sign Scott Downs or Matt Thornton or Javier Lopez for 2014 and maybe even beyond, but if they flinch at longterm deals for left-handed specialists and decide to use their prospects, O'Flaherty could be a worthy investment.
From 2012 to 2013, the Yankees signed David Aardsma to a $1 million contract. He pitched exactly one inning in 2012 as he recovered from injury, but the signing was really for the 2013 season. The Yankees could sign O'Flaherty to a similar deal in hopes that he can get back to the mound next season.
Seeing as this is an investment for the future, the Yankees should only consider signing him until they have completed their offseason plans. If no team has scooped him up before then, the Yankees should take a chance on him. They ultimately ended up cutting Aardsma in spring training, so if O'Flaherty ends up as a similar bust, no one is going to miss him.