The 41-year-old will take charge of the Blues in just his second season of senior management.
And former West Ham and Tottenham boss Rednknapp thinks his relative will have his work cut out for him
“It's going to be a tough season for Frank," Lampard's uncle Harry Redknapp told Football.London.
“It's great to see him get the opportunity at Chelsea and I'm sure he'll do well in the long term, but they've lost their best player in Hazard.
“He's got a big job and it's going to be a tough year. If they make the top four, and I think they can finish fourth, it'll be a big achievement."