TAMPA, Fla. -- Aaron Hicks has not played since March 1 and his ailing lower back required a cortisone injection during Monday's team off-day, but the Yankees center fielder said that he is "not really" concerned that the discomfort could delay his availability for the start of the regular season.

"If I need to get at-bats, I can go down to the Minor League side and do that," Hicks said prior to Tuesday's Grapefruit League game against the Orioles. "I feel pretty good today. [Feeling] no pain is a big thing for me, especially when it comes to swinging. Until I start doing something like that, I won't know for sure."

The treatment came one day after manager Aaron Boone said that the switch-hitting Hicks ran, played catch and took swings from both sides of the plate. Hicks said that he continued to experience restrictions with his mobility, especially while hitting and throwing.

"I think they just wanted to be certain because he is still feeling a little something," Boone said. "It wasn't overly invasive. They just felt like it was the right thing to do."

Because of the injection, Boone said that Hicks is not expected to play before the weekend. He added that the Yankees are "not close" to the point where Hicks' availability for the March 28 season opener would be in jeopardy.

"There's a level of concern, but I'm confident that we're treating it real conservatively and making sure it's all out of there so he can hit the ground running," Boone said. "I'm not too worried about it, but any time one of your players is out for an extended period, you've got to have some concern."

Should Hicks not be ready for Opening Day, the Yankees could shift Brett Gardner to center field and have Giancarlo Stanton patrol left field. The open designated-hitter slot would potentially create an avenue for the club to carry both Greg Bird and Luke Voit. Outfielder Clint Frazier could also be considered.

Hicks, 29, has played in four Grapefruit League games this spring, collecting two hits in nine at-bats. He agreed to a seven-year, $70 million contract extension that was announced on Feb. 25.

"Something like this that's been lingering, you've got to do something about it," Hicks said. "I think at least by me getting [the injection], I'll probably lose like three or four days and get on the field after that. As of right now, I don't know when I'll get in there."