Denmark international Okore suffered cruciate ligament damage in last weekend's home defeat to Newcastle which will rule him out for the remainder of the season.
The news this week came as a major blow to Lambert, who signed the player from FC Nordsjaelland in a bid to shore up a leaky defence which left his side battling relegation for most of last season.
"The initial injury has happened and it's a blow to him," the Scot.
"But in years gone by if you did your cruciate you were struggling to play again but now it's a run of the mill thing that players come back strong and I'm pretty sure he'll do that.
"He's only young so he'll be fine.
"He'd started the season well, especially considering he missed a big bit of pre-season, so it's a blow for him and certainly a blow for us."
Clark, 23, and Baker, 22, must now fill in for Okore between them until at least January.
But despite their occasional errors last term, their manager has full faith in both men to stand strong alongside captain Ron Vlaar.
"They're young so they're going to make mistakes," he said. "But towards the end of last season they were great and now they've had a year at it, playing consistently, they'll be better for it.
"I don't have any problems with Ciaran and Nathan at all and I don't need to think about bringing in any loan signings."
Okore faces nine months of rehabilitation and Lambert is keen to keep the youngster involved in day-to-day proceedings as he adjusts to life in a new country.
"He'll have good days and bad days because of the length of time he's going to be out," he said.
"It's normal because when you're a footballer and you're out for a long time it can weigh you down when you come into work.
"But he'll be all right because he's got a good group around him who will help him."