Johnson said that he tweaked his back after catching a spike in a turf mat around the batting cage at Bright House Field. Had it been the regular season, Johnson said he would have played "for sure."
"I felt a little something back there, and I could have played," Johnson said.
Johnson, 31, began his second tour of duty with the Yankees on Wednesday, entering the club's Grapefruit League opener against the Pirates in the fifth inning. He saw duty at first base, going 1-for-2 with a run-scoring double.
Johnson said he is not concerned by the back stiffness, which he thought could have been avoided by wearing turf shoes instead of spikes during batting practice.
"It won't be too long," Johnson said. "I'm not really worried about that."
Yankees manager Joe Girardi said that he might give Johnson another day off Friday against the Rays at home, just to make sure there are no lingering effects.
"You're cautious in Spring Training, because it's a time when you can give guys a couple of days," Girardi said. "As a DH, you can make up at-bats pretty easy, where you're not really going to get run down. You're hitting, and it's not quite as taxing."
Johnson signed a one-year, $5.75 million contract with the Yankees in January, replacing World Series Most Valuable Player Hideki Matsui as New York's DH.
The Yankees have said they hope that using Johnson as a DH will help to keep him on the field, despite his long injury history.
"He's had some injuries, there's no doubt about it," Girardi said. "We've had to manage other players that have had injury problems and you worried about them, last year or the year before. We'll be able to take care of that, I think."
Jamie Hoffmann replaced Johnson as the DH on Thursday, logging a hit in three at-bats.
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.