The Danish defender, who was signed from Nordsjaelland for £4million in the summer, is set to spend up to nine months on the sidelines after rupturing his anterior cruciate ligament on the weekend but Lambert is confident Ciaran Clark and Nathan Baker are good enough to hold down the central defensive positions.
"They're young so they're going to make mistakes," he said ahead of the trip to old employers Norwich City on Saturday.
"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."
Of the Okore injury, Lambert added: "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.
"But he'll be all right because he's got a good group around him who will help him."