The Croatian was suspended at Brighton on Monday following his FA Cup final red card, but is back in place of Ruben Loftus-Cheek.
That means Kai Havertz and Timo Werner make their Stamford Bridge debuts from the start, and Reece James is again preferred at left-back. Jorginho is captain on the occasion of his 100th Chelsea appearance.
Explaining his team selection, Lampard said: ‘It’s a change from my point of view. Different games bring different problems. We’re playing the team that were the best in the country by a long way last season and Kovacic gives you some presence in midfield.
‘We want to play and get on the ball. Against Brighton it was tough for us to do that for different reasons but today hopefully we can get more of the ball there.'
Liverpool make one change from their opening-day win over Leeds, with Fabinho replacing Joe Gomez and expected to play at centre-back. Their new signing Thiago Alcantara is on the bench.
Chelsea (4-3-3): Kepa, James, Christensen, Zouma, Alonso, Kante, Jorginho (c), Kovacic, Havertz, Werner, Mount.
Subs: Caballero, Tomori, Azpilicueta, Barkley, Hudson-Odoi, Abraham, Giroud.
Liverpool (4-3-3): Alisson, Alexander-Arnold, Van Dijk, Fabinho, Robertson, Keita, Henderson (c), Wijnaldum, Salah, Fabinho, Mane.
Subs: Adrian, Tsimikas, Thiago, Milner, Jones, Minamino, Origi.