The 28-year-old made 50 appearances in City's 2022-23 campaign, scoring five goals and registering 11 assists to help his side win the Champions League, Premier League and FA Cup.
However, his playing time has been limited this season due to injuries. Grealish has made 31 appearances in all competitions this campaign, scoring three goals with three assists.
He returned to action at the end of March and played a key role in Tuesday's 3-3 draw at Real Madrid in their first leg of the Champions League quarter-finals.
"We are really pleased (with Grealish)," Guardiola told reporters on Friday. "We miss him. He has to continue until the end in that level.
"He has to improve in some departments, finishing for example, but this is the Jack we know of last season that helped us again to do it.
"This season unfortunately he could not be there (throughout). But I'm pretty sure he has learned the lesson and try to help us in the next half.
"Not (just) next year but the years he has ahead of him for his career (hopefully he) can perform in that level."
