Keane agrees with caretaker boss Lennon that major surgery is required at Parkhead this summer following the club's limp surrender in Saturday's Scottish Cup semi-final at Hampden.
"If he's the manager of the football club and he's suggesting that, I'm sure that has to be the case," said on-loan Tottenham striker Keane, who hinted former boss Tony Mowbray's January recruitment drive may have backfired.
"I'm sure there will be a lot of changes in the summer. It's obviously been a difficult year for the club itself and the change it has had and the players who have been brought in.
"A lot of players brought in, a lot of players have left. It's been the biggest clearance.
"A lot of players coming in at the same time, which can sometimes be difficult, and obviously that (Saturday's defeat) has proven it."
Lennon looks set to make changes for tomorrow's Clydesdale Bank Premier League game against Motherwell.
"He has every right to," Keane added. "I don't think anyone could go in and knock on his door and have any complaints, and say, 'Why aren't I playing?'
"He'd just show you a video of Saturday's game and say, 'That's why'."
Lennon was scathing about his players following their Hampden humbling, singling out one or two for particular criticism.
But Keane insisted the entire team had to carry the can for a performance widely regarded as among the worst Celtic have ever produced.
Asked if it was an all-time personal low, the 29-year-old said: "Yes, considering where we could have gone from there.
"We could maybe have won a medal so, in that circumstance, it's difficult to take.
"I obviously wanted to come up here and win something. It wasn't to be but I'm still going to enjoy the remaining time that I have left here."
Saturday's result capped a nightmare spell at Parkhead for Keane, who had hoped to rescue Celtic's season when he was unveiled in front of thousands of jubilant fans just over two months ago.
But despite being set to return to London empty-handed this summer, he insisted he has no regrets about his decision to come north.
"I never regret anything I do in life," said Keane, who can take pride in the individual form which today saw him named Clydesdale Bank player of the month for March.
"At the end of the day, I'm playing for a wonderful football club, which I've always wanted to do since I was a little kid. Great if I'd won something - it's not the case.
"I'll continue to give 100%, which I've always done in my career."
Like many of his team-mates, Keane absolved Lennon of blame for the Ross County debacle, but stopped short of endorsing the caretaker's bid to succeed Mowbray on a permanent basis.
The striker is braced for a hostile reception tomorrow and would not blame supporters if they stayed away.
"Of course we'd like as many fans to be there tomorrow as possible," he added. "If not, what can I do about it? Are you going to cry about it?
"We have to get a bit of pride back into this team."