Despite having handed the club's record signing just six starts so far this term, the Scot is adamant that he is not eager to move the 28-year-old on in January
The 28-year-old is currently sidelined by an ankle problem, but had lost his place in Lambert's starting line-up to summer signing Christian Benteke.
But, despite having named Ron Vlaar as captain ahead of Bent during Stiliyan Petrov's continued absence with illness, the Scot has underlined his desire to retain the England international.
"I'm not actively looking to sell him," he told reporters.
"There isn't an issue, at least not at my end. It's just back to the injury and I have to look after another 20 lads.
"I have to pick a team I think will win. I've always done that. Everyone has to show their worth. I have no favourites. I judge them as equals."
Bent has scored twice in nine Premier League appearances so far this term.