The Sabres host the Stars on Thursday and the Flyers on Saturday before heading to Ottawa to play the Senators next Tuesday.
"Big thing is to get him integrated in practice, see where he's at," Granato said. "… We'll get another practice in tomorrow and we'll see where he's at."
Mittelstadt, 23, was poised to enter the season as Buffalo's top-line centerman after tallying 17 points in 22 games to end 2020-21. He sustained an upper-body injury during the season opener against Montreal, forcing him to miss more than two months.
Mittelstadt returned to the lineup on Dec. 2 and played three games before sustaining another upper-body injury in the same area during a home game against Anaheim. He underwent surgery on Dec. 10.
"I'd be lying if I said it wasn't hard, especially the first couple days after," Mittelstadt said. "I don't know. Just turn the page and start going again. I'm not the only one who has been through it, so get back to work and the faster, the harder you work, the faster you're going to get back.
"For me, that was my goal and obviously, it's hard to watch the team and not be able to be out there with the guys and be around the guys every day. That's been my motivation for getting back, getting back into the lineup, going out there and helping the team."
Mittelstadt said the surgery gives him peace of mind moving forward.
"He had the surgery and he has a different level of confidence," Granato said. "He knows he's fixed, he's repaired, he's ready to go. So, it's a whole other level of confidence with respect to, it's a complete known. 'I know I'm ready to go, I know it's fixed, repaired, whatever.' And that's much different than where he was six weeks ago, and he's going to be better because of it."
Below are more updates from Thursday's injury report: