Yankees manager Joe Girardi second-guessed himself.

Should he have played Jacoby Ellsbury in favor of Brett Gardner in Tuesday's wild-card game against the Astros? Was there anything he could've done to mitigate his team's second-half decline? Should he have rested his players better?

"I did the best I could is the bottom line and people thought I could've done better and I understand that," he said in a season-ending news conference at Yankee Stadium on Friday morning. "You live with it ... You always try to put a reason on certain things, try to understand."

Even though he was full of questions, Girardi had a few answers. He played Gardner, he said, because he had a stronger body of work against left-handed pitchers, and at that time, he thought it would be his best bet against Astros starter Dallas Keuchel. "Did it work out? No," Girardi said. "If I would've played Ells, would it have been better? Would it have been three runs better? I don't know."

He wasn't quite sure about the team's second-half swoon but said he would have to strongly evaluate how and when he plays certain guys, so as not to burn them out too soon. He also said that despite his rotation flaws -- the Yankees were 17th in the major leagues with a 4.05 team ERA -- he was confident this staff could lead them into next year.

"I think you're going to see improvement out of our starting pitchers," he said, mostly because guys such as Michael Pineda will come into their own, and because Masahiro Tanaka and Ivan Nova will continue to heal from nagging injuries.

At this point, he said, CC Sabathia, too, likely will be a starter. Sabathia announced on Monday that he would enter alcohol rehab but was expecting to be back pitching for the Yankees in 2016.

"I think we had a lot of questions answered and I feel a lot more comfortable moving forward," he said.