Grealish to miss Manchester City's match against Chelsea, Bernardo Silva a doubt
The winger had to be replaced in the first half after picking up a groin injury in Tuesday's 3-1 victory at Copenhagen in the first leg of their last-16 Champions League tie.
"All I know (is) he is not available tomorrow," manager Pep Guardiola told reporters on Friday.
City can reclaim the league lead from Liverpool on Saturday, although because they have a game in hand, the better barometer will be when Brentford visit on Tuesday and Guardiola's side catch up in number of games played.
"We just need to win our games," Guardiola said about the tight title race. "When we arrive with eight or nine games (remaining this season) we will see how many teams will be involved.
"It doesn't matter if there are two, three or four (teams fighting for the title), we just need to do our job."
Liverpool have 54 points after 24 games, while City, unbeaten in their last eight league games, are second in the standings and level on points with third-placed Arsenal (52). City have also played one fewer game than Arsenal.
Guardiola said while Mateo Kovacic and Sergio Gomez returned to training and so will be available on Saturday, he was uncertain of Bernardo Silva's status.
"Bernardo we will assess in today's training session," the manager said.
Saturday marks the return of Cole Palmer to the Etihad after the 21-year-old, who came up through City's academy program, moved to Chelsea on the final day of the summer transfer window.
Palmer told reporters it will be a "weird feeling" to return, while Guardiola had kind words for his former player.
"Good player," he said. "I didn't have any doubts (that Palmer would play well for Chelsea).
"He is a star player and is already an exceptional player and moved on. A lovely lad and he helped us achieve what we achieved."