"Today was definitely a step in the right direction," he said. "I got in my catcher's squat and started moving around a little bit, played long toss and hit. I'm looking forward to coming off [the disabled list]."
Astros manager AJ Hinch said Tuesday was a big day in terms of McCann's recovery.
"If he gets through today, that's a really good sign," Hinch said. "He's not factoring into this series, but hopefully after today we'll have a better timeline. Is he going to hit the 10 days? Is he going to need more time? What's next for him?"
McCann said the beauty of the 10-day disabled list is that he won't need a Minor League rehab assignment, but he knows he's going to have to manage his knee the rest of the season. He was on the DL last August with the same issue, which is a result of wear and tear.
"I just needed my knee to calm down," he said. "I got the fluid out and I'll be ready to go."
McCann, 34, is hitting .219 with four homers and 14 RBIs in 114 at-bats this season. After a good start at the plate, he is in a 1-for-26 slump.
Reddick to return Wednesday Astros outfielder Josh Reddick, who's been on the DL since May 20 with a staph infection above his left knee, went 3-for-4 in his second rehab game at Double-A Corpus Christi on Tuesday night and will be activated prior to Wednesday's game against the Mariners, Hinch said, starting in right field. J.D. Davis will be optioned to Triple-A Fresno.