Gardner said that he has repeatedly felt some discomfort in the thumb since he fractured it last season, but that rest usually allows him to get back in the lineup the next day.
Kevin Russo was in New York's lineup to play left field instead, though Gardner did enter Wednesday's game as a pinch-runner, scoring a run in the eighth inning of a 4-2 win over the O's. Gardner said that he expects to have a MRI performed on Friday in New York.
"Nothing's set in stone yet," Gardner said after Wednesday's game. "I definitely felt better today once I got some treatment on it. Hopefully I'll be able to swing a bat [Thursday] and we'll go from there."
Gardner fractured the thumb last July 26, sliding into second base against the A's in the first inning, then played nine more innings before postgame X-rays revealed the break.
Yankees manager Joe Girardi said that Gardner is strictly a pinch-runner at the moment, unable to bat in a game or throw.
Gardner had treatment on the thumb Wednesday and that it felt better, which has him hopeful that it is only a strain or tweak, and he can be considered day-to-day going forward.
The speedster said he felt the pain after a sixth-inning check-swing facing Orioles starter Kevin Millwood on Tuesday, and again when he singled in the seventh inning. Marcus Thames pinch-hit for Gardner in the eighth, and Gardner said the injury can be attributed to bad luck.
"How many swings did I take since I started hitting in the offseason? Probably thousands and thousands," Gardner said. "It's frustrating the way it happened for me, but there's nothing I can do about it."