Lampard, who is 36 in June, is out of contract at the end of the campaign alongside captain John Terry and Ashley Cole, a trio who have been mainstays at Chelsea for eight years and more.
"Frank Lampard is ill, he is in bed," Mourinho said.
"If he is in bed on Friday, I don't think on Saturday he is coming in a condition to travel or to play."
Lampard is Chelsea's record goalscorer, with 211 goals in 646 appearances since his 2001 move from West Ham.
Asked to reflect on Lampard's distinguished career at Stamford Bridge, Mourinho added: "Maybe in a few years he will have a statue where Peter Osgood is, by his side
He's one of the biggest players (in the history) of this club."
Terry is also doubtful - with "a little thing" picked up on Thursday - but has begun negotiations over a possible new contract and his form this season suggests the Blues would like to keep the captain.
England left-back Cole appears on the verge of an exit after being a peripheral figure this term.
Mourinho, who will provide a report to the Chelsea hierarchy at the end of the campaign, was unable to provide an update on the futures of the trio.
Asked if their Chelsea careers would end at the season's conclusion, Mourinho said: "I don't know
But I don't think so
The club knows my opinion
The players know my opinion too."
Despite finishing the season without silverware - Chelsea's first trophyless campaign since 2010-11 - Mourinho reflected on a "positive" return.
Other managers have paid with their jobs in similar circumstances under notoriously hard-to-please owner Roman Abramovich, but the Portuguese is likely to remain after guiding Chelsea back into title contention for much of the campaign, after the Blues finished 25 points off the pace in 2012 and 14 adrift last term.
"By the competitive aspect I think it was an evolution," Mourinho said.
"Some of the players had for the first time that experience of fighting for the title, until it was not possible, and fighting for the Champions League, playing Champions League knockout phase, quarter-finals, semi-finals.
"This is not the kind of season that Chelsea celebrates, because this is Chelsea's nature and my nature.
"We are not jumping because in such a difficult Premier League we finished third and qualified to the Champions League group phase without play-offs.
"In this moment we are thinking about next season
We are turning our focus not to the World Cup but to preparations for next season."
Mourinho has often spoken of transition since returning to Stamford Bridge and he will have decisions to make this summer.
As well as the futures of Terry, Lampard and Cole, Chelsea and Mourinho have other things to ponder.
What to do with his goalkeepers, Petr Cech and Thibaut Courtois, who has excelled on loan at Atletico Madrid?
What to do with Romelu Lukaku, who has scored 15 times on loan at Everton?
Mourinho has often spoken of the travails of his strikers - Samuel Eto'o, Fernando Torres and Demba Ba - and his desire to recruit a prolific goalscorer, with Atletico's Diego Costa widely linked.
Eto'o, who has scored 12 goals this term, all at home, is out of contract at the end of the season and may also have played his final game for Chelsea as he suffered an injury in training on Friday after a recent knee problem.
Mourinho and Chelsea have been working on the recruitment of a striker for some time.
"We were preparing the long-term future and not just an immediate solution to try to help us for the rest of the season," Mourinho said.
"In the same way we bought two players in January and they were not eligible to play in the Champions League (Nemanja Matic and Mohamed Salah) and we said 'no problem' because we are preparing the team for the long term and not just for the immediate.
"It is normal that we are going to bring a striker (in) now
It's normal
It's normal that we want to improve.
"We have good strikers, we have good players, we are not in a desperate situation.
"But it's the normal evolution of the team
Every team wants to get the summer transfer window to improve and one area we want to improve - and we've made it very clear since December, January - that it's the striker position.
"We have three strikers in this moment
Normally one is coming, normally one is leaving
Calm, natural and logical."
Source : PA
Source: PA