The 41-year-old thinks the England midfielder may need longer to recover from games but believes he can change his playing style to maintain high performance levels
The 33-year-old has been a key man for the west London club for over a decade but has seen his playing time diminish this season, especially under former boss Andre Villas-Boas.
However, the England man has still managed to net 10 goals in his 25 Premier League appearances so far this season and the Blues' interim coach refuted the idea that his player is in decline.
The Italian told Sky Sports: "I wouldn't say he's entered a declining stage.
"What I can say from my own experiences is that you probably need a little bit more time to recover when you get to a certain age.
"Apart from that, if you're healthy and fit, you can reach high levels."
The 41-year-old turned to Manchester United's returning midfielder Paul Scholes as an example of how the midfielder can adapt to stay competitive at the top level.
He added: "Paul Scholes is not bursting forward as much as he used to do. But Frank's an intelligent guy, so he will adapt very quickly to that.
"I have no problems with age if somebody is healthy and fit. He's a top professional. I think this club has been blessed to have a player like him for 10 years."
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