Over the last few offseasons, the Yankees have only spent whatever comes off the books following the season. They put the money back into the team and that’s basically it, no more. The Yankees only shed about $20M in player salaries after the 2015 season, and a little less than half that will go to covering arbitration raises. It’s no surprise they’re focusing on trades now.
Spending some (any) of those limited dollars on a relief pitcher may not seem like a smart idea, but with substantial rotation help unlikely to be on the way, improving the relief crew make sense.