Real Madrid boss Mourinho is the red-hot favourite to fill the Stamford Bridge vacancy this summer with interim boss Rafa Benitez stepping aside after Sunday's Premier League finale with Everton.
The Portuguese coach enjoyed huge success during his first four-year spell in West London, winning back-to-back Premier League titles on top of securing FA Cup and League Cup glory.
Chelsea's last title triumph came in 2010 under Carlo Ancelotti and Lampard, who signed a new one-year deal with the club on Thursday, believes that Mourinho's anticipated comeback could help them challenge Manchester United and Manchester City.
"Our league consistency hasn't been good enough these last two years. That's something we must address this summer," he said.
"City and United have raised the bar and we need to get back to that battering ram mentality we had before, winning games 1-0 even when we're not at our best.
"We need to be able to close ranks and grind out results again as too many times in recent years we've had a bad month when everything has dropped away.
"When we won the title under Jose we were criticised for the fact we were so dogged but we certainly need to get some of that mentality back in our game.
"It doesn't mean taking away the beautiful football entirely because we have to cater for the creative players we have and get them into our team. But there has to be a happy medium because challenging for the league again next season is a huge priority and if Jose does come back it will be a huge lift for this club.
"He's the greatest manager in Chelsea's history and changed the whole mentality of the place to turn us into a winning club.
"The fans idolise him and those players who haven't worked with him before will soon understand that he'll come in and give them the extra edge that will turn us back into a consistent force."