NEW YORK -- Chad Green's rookie season has been an interesting one.
His time spent in the Minors has been spectacular, where he's the Triple-A International League's leader in both ERA (1.41) and WHIP (0.90). But his time in the Majors has been complicated, as he's been asked to wear a variety of different hats. He's started, he's worked out of the bullpen, and he's even been asked to hit a couple of times.
Thursday morning, Green was called up yet again, his fourth callup of the season. (As a counter-move, the Yankees optioned Nick Goody to Triple-A Scranton/Wilkes-Barre.) But this time, Green said he's not even sure what hat he's going to be asked to wear. Green said upon arriving that he had "no clue" whether he was going to be starting or coming out of the bullpen this time around.
Green relieved CC Sabathia with 2 1/3 scoreless innings in the Yankees' 4-1 loss to the Orioles in the series finale.
Before the game, Girardi conceded that there was a chance that if Green wasn't used Thursday, the manager and the staff would have discussed starting him Friday instead of Masahiro Tanaka, in order to give Tanaka an extra day of rest. 
On four days' rest this season, Tanaka has posted a 5.33 ERA. On long rest, Tanaka has been borderline unhittable, posting a 1.70 ERA and a WHIP of 0.89.
Girardi also made clear Thursday that going to a six-man rotation for Tanaka's benefit isn't as simple as it seems.
"People talk about a six-man rotation," Girardi said. "The only way you can do a six-man rotation is if you have a 13-man pitching staff. I don't think with our club we're really equipped to do that. People say, 'Oh, just use a six-man pitching.' But you still need your seven relievers. Just because you go to a six-man rotation doesn't mean you're going to get more distance. So you can't really keep it a 12-man staff. So it creates problems."
The biggest deterrents for Girardi in going to a 13-man pitching staff seem to be length, age and versatility. When it comes to length, that's just a product of the times. The Yankees have actually gotten above-league-average length from their starters this season, but the rotation still averages fewer than six innings per start, a fact that is taxing on the bullpen and requires a consistently fresh stable of at least seven men.
That number is where the other two factors come in. Combining seven relievers with six starters obviously expands the staff to 13, but it also deflates the bench to just three position players. And with the Yankees' average age being the highest in baseball and the versatility restrictions that come with carrying the likes of Alex Rodriguez, Carlos Beltrán and Mark Teixeira, all of whom need days off and occasional-to-frequent DH days, a short bench isn't a luxury that Girardi can afford.
So, with the Yankees' roster built the way it currently is, it doesn't seem likely that an expanded rotation will come any time soon. It just creates too many problems. But, as Girardi said: It's still possible.