Frank Lampard has performed better than expected at Manchester City and Owen Hargreaves insists the Premier League champions can't afford to let the midfielder walk away.
The 36-year-old is due to head to New York City in the new year, but he has become a crucial figure during his loan spell at City.
And Hargreaves believes that Manuel Pellegrini should do anything in his power to keep Lampard in his squad.
“Anyone who knows Frank will tell you what a great guy he is, and a top professional. He also brings all of his experience to the dressing room, not just playing-wise.
“His plan was always to go to New York, but I don’t think City can afford to lose him, especially with the injuries they have. They don’t really have a replacement if they do lose him.
"“That is even more so with Yaya going to the African Cup of Nations. That means Fernando and Fernandinho will take on a more important role and probably play as a defensive midfield pair, which also would not be a bad thing, as City have so many attacking players and, in my opinion, have two of the best attacking full-backs out there in Zabaleta and Kolarov."
Hargreaves also suggested that even Lampard may be surprised by how effective he has been at City so far.
“I think if you asked Frank he would be surprised by the impact he has made!" he said.
"You wouldn’t think he would just walk in, but with the injuries and issues any team has, and the impact he has made coming on in games, he has made a big impact.”