Girardi was encouraged by Phil Hughes' five innings of two-run ball in Wednesday's 5-2 win over the Rays and said that he isn't any closer to figuring out how six arms will fit into five slots.
"I like the way our guys have thrown the ball," Girardi said. "Some of the numbers aren't great, but I've been pleased with the way our starters have went about their business and competed for this. This is going to be a difficult decision."
Ace CC Sabathia (4.50 ERA in eight spring innings) is assured of his Opening Day start on April 6 against Tampa Bay, and Hiroki Kuroda (4.00 ERA in nine innings) figures to be a lock after signing a $10 million deal in January.
Hughes (2.02 ERA in 13 1/3 innings) has had a resurgent spring after a disappointing 2011, while Ivan Nova (7.82 ERA in 12 2/3 innings) and Michael Pineda (3.97 ERA in 11 1/3 innings) have created concerns about their command and velocity, respectively.
The Yankees plan to have their sixth contender, Freddy Garcia (4.50 ERA in eight innings), back in play on Saturday against the Tigers after suffering a bruised right hand earlier in camp.
"I think when you're on the mound, that's the last thing you want to think about," catcher Russell Martin said. "I think they're just trying to pitch to the best of their ability. It just so happens that there is a competition within the team, but that can't be your mindset when you're on the mound. You've just got to worry about, 'What pitch am I throwing next?'"