Milner was forced to sit out the victory over Aston Villa on Sunday due to a minor muscle issue the Reds didn't want to risk.
Lovren has been absent from the past two matches with a knock, while Joel Matip is set to miss the remainder of the season with his foot injury.
There was, however, a return for Xherdan Shaqiri on the weekend, with the No.23 part of a matchday squad for the first time since January.
Brighton, meanwhile, will definitely be without Jose Izquierdo, with Steven Alzate also a doubt.