TAMPA, Fla. -- New York Yankees slugger Aaron Judge resumed on-field batting practice Thursday and said he is not focusing on a timeframe for returning to the lineup.

Yankees manager Aaron Boone said Wednesday it is possible Judge could return in time for New York's games against Boston in London on June 29 and 30, the first major league regular-season games in Europe.

"I'm taking it day to day," Judge said. "The minute I start thinking about when I'm going to come back, when I'm going to do that, then my hopes might either go up or down if I get pushed back or some thing like that. So I'm just focused on getting better every day."

Judge strained his left oblique muscle on April 20. He is now pain free and working out at the team's minor league complex.

"Now it's just going through the protocols so I can finally get out there," Judge said. "They haven't been needing me the past couple weeks, so I'm going to take my time and make sure I get healthy and get ready so I can help them down the road."

Even with a large injured list that also includes ace Luis Severino and slugger Giancarlo Stanton, the Yankees entered Thursday leading the AL East by 1+ games over second-place Tampa Bay.

Judge, who has been hitting in an indoor cage, also continued increasing his defensive work in right field

"It's good to finally get outside and get some fresh air when I'm hitting now," Judge said.