BALTIMORE — The Yankees don’t expect outfielder Giancarlo Stanton back before rosters expand in September, but he has started baseball activities, according to manager Aaron Boone.

“He hit off the tee [Tuesday], still doing light running on the treadmill. He is definitely moving in the right direction,’’ Boone said of Stanton, who is on the IL with a sprained right knee.

Luis Severino and Dellin Betances threw on flat ground in between rain showers on Wednesday at Camden Yards. Severino can’t wait to make the next step.

“I have never been more excited throwing a bullpen than Friday,’’ Severino said before the Yankees’ 14-2 blowout win over the Orioles.

The last time the former staff ace was on the mound was in spring training, before his right shoulder impingement was discovered. Working his way back from that, the right-hander suffered a lat injury.

Severino estimated he will throw 25-30 pitches in a Rogers Centre pen.

“I was out there watching from afar, both those guys,’’ said Boone, who has been without Severino and Betances all year. “It looks like they came out of it well. I think Dellin, if everything goes well this weekend, he could be on the mound maybe on Monday when we get back home.’’

According to Betances, he will throw on flat ground Friday and Sunday but doesn’t know when he will get on a mound.

Out since July 27 because of an inflamed right knee, CC Sabathia will take a step toward coming off the IL with a bullpen session Saturday or Sunday.

“If everything goes well, maybe next week [off the IL],” Boone said. “Where he slots in, I am not sure. We want to make sure everything is good to go. If it goes well, there is a chance you could see him on the homestand.’’

The Yankees open an eight-game homestand Monday with a doubleheader against the Orioles. Since they used reliever Jonathan Holder to start this Tuesday night’s game, the Yankees could slot Sabathia in late in the week or over the weekend, when the Indians are in The Bronx for four games.