Frank Lampard believes a contract renewal for manager Antonio Conte would represent Chelsea's best signing of the close-season.
Conte has been offered a new contract to extend his deal at Stamford Bridge beyond 2019, following claims he was concerned at the club's transfer inactivity.
Everton striker Romelu Lukaku, Monaco midfielder Tiemoue Bakayoko and Juventus wing-back Alex Sandro are among the targets being linked with the Blues.
But former Chelsea star Lampard feels renewing Conte would be the best coup of all after leading the club to Premier League glory in his first season.
"Antonio would be their most important signing – for me he was their man of the season," Lampard said in quotes reported by The Sun.
"He took the club from 11th to comfortable champions and that can't be underestimated.
"I think he's a huge signing for them. You talk about player of the year, I'm all for giving the players credit but because it was such a dramatic uplift from the year before I think you have to give him huge credit.
"You saw the system change and how he made them play in that formation, it worked well.
"I think he's a huge signing for them. I have no doubts, I don't know, but I'm pretty confident he'll be there and they'll bring in players to play in the system he wants to play."