First Pitch: Robertson returns

Picking relief pitchers is like choosing stocks. It helps to know a little more, but still no one really knows.

David Robertson is expected to return from his groin injury on Tuesday in Boston. We know a lot about him, but we still don't know if he is a full-time closer.

He is 2-for-2 and has yet to allow a run in his three innings. Still, one outing was in Houston and the other was in Toronto. A save is a save, but we haven't seen him do it in Boston without the Mariano Rivera safety net.

Robertson should be fine. He has stuff that is pretty dominant for a reliever. His combined ERA the past three years is 1.91, while his strikeout per nine innings is 12 over that same period.

With Robertson hurt, Shawn Kelley earned some respect -- and probably some confidence. Kelley has appeared in an AL-most 10 games as of Monday night, throwing 9 2/3 innings with a 1.86 ERA. He saved four games. He lost one in a non-save situation.

With the emergence of Adam Warren and Dellin Betances combined with veteran Matt Thornton, the Yankees might be able to glue the bullpen together in the post-Mo era.

Still, we need to see how Robertson, Kelley and the rest handle the big spots. In Fenway is as good a place as any.

Pitching Matchups: Here are your Yankees-Red Sox pitching matchups:

Tuesday: Masahiro Tanaka (2-0, 2.05) vs. Jon Lester (2-2, 2.17)

Wednesday: Michael Pineda (2-1. 1.00 ERA) vs. John Lackey (2-2, 5.25)

Thursday: CC Sabathia (2-2, 5.19) vs. Felix Doubront (4-4, 5.48)