The defender was involved in a nasty clash of heads with team-mate Franck Kessie eight minutes from the end of normal time of the 1-1 Europa League draw in Seville.
Musacchio appeared to have lost consciousness but it was reported after the game that the 28-year-old was able to walk through the mixed zone and assure reporters of his health.
Speaking to Sky Sport Italia, Gattuso said: "Musacchio's injury was a collision, but knowing his temperament, he'll do everything he can to recover and play this weekend."
Hakan Calhanoglu also went off with a foot injury, the problems mounting for a Milan side that could be without Gonzalo Higuain, Giacomo Bonaventura and Davide Calabria against Juventus this weekend while Lucas Biglia and Mattia Caldara are long-term absentees.
"Calhanoglu had the usual knock to the top of the foot. We'll see," Gattuso added.
"I have to wait for what the doctor says, as I am a coach and not a doctor. There's no point thinking about it, we'll play who we've got and will wage battle, as looking for alibis will get us nowhere.
"Now we've got two and a half hours to fly back and do some work on the plane. Juventus are one of the best sides in Europe, let alone Italy, but we won't sit here crying into our hankies. We'll face them and play our football."
Milan responded well after a disappointing first half in which they fell behind to a Giovani Lo Celso opener, Suso's free-kick earning a share of the spoils in the Group F encounter.
"It's good to play well, but there is some bitterness. Our wing-backs were too deep in the first half and never pushed up, so we did better after moving to 3-4-3," Gattuso said.
"We conceded a goal early through our error, but the lads deserve credit because they fought back and showed character to get a result in a difficult arena.
"Once again tomorrow, we'll have to count to see how many players we actually have left."