"James is a good signing for Manchester City," said David James. If the former England goalkeeper is unsure if he can live up to his record price,
Greelish became the most expensive British transfer since his 100 100million move from Aston Villa to the Premier League champions last year.
The 26-year-old has not played his best for Villa, but has made 26 to 31 appearances in all competitions.
With just four goals scored in those games, Pep Guardiola happily used the Green League as a substitute, giving City the chance to win three domestic and European trophies.
Grealish's price tag hangs over his head, but We believe that providing more silverware will make the transfer fee worthwhile.
"You can not ignore the money," James told Stats Perform. "But whether it is good or bad, There will be no fair price or pricing, whether it is bad or bad.
"Greelish have been heavily involved in City's games this season, [they] are at the top of the league, in the Champions League quarter-finals and in the FA Cup semi-finals.
"Jack Grealish was there. He is a very successful part of the team at the moment. It was a good signing."
Greenwich were involved in 16 Premier League goals (six goals and 10 assists) at Villa last season, but only four so far.
He made a total of 81 laps in the top races last season, averaging 3.3 times per 90 minutes. It has dropped to 43 this season (2.5 out of 90).
However, James believes that James has given new impetus to Grealish's game, such as becoming a team player in a star-studded club.
"What I like most about Jack is that he has a different side than the way he played at Aston Villa," he said.
"As influential he is, just as Jack needed to get Aston Villa to work, [City] do not have to agree in the same way. Manchester City do not need Jack for City.
"He needs to be part of a bigger team. I think he succeeded. I think he was a successful call.
"If Manchester City want to win the League Cup, if they can win the FA Cup, they will be a big part of Jack Grealish at the club."