The striker has spent his entire career at the club and is approaching the final 15 months of his current deal at Villa Park, having made his first professional appearance for the club in 2006.
But Lambert, who compared the 27-year-old to Manchester United's Ryan Giggs, claims there is no rush to get a new contract agreed as there is still plenty of time remaining.
"A one-club man is very rare," he told reporters. "Ryan Giggs was the last one, there are not too many now.
"Gabby has been here since he was a young guy but, as for his contract, 15 months is still a long time in football – you used to not find out until a week before the end of season.
"It's strange in football, there's a long way to go."
Agbonlahor has been out of action since October 26 and is set to miss Saturday's clash with Cardiff City, but Lambert revealed the striker is still happy at his boyhood club.
He continued: "He's enjoying his football, it's a bit frustrating at the moment but the important thing is for him to be fit for us after the break.
"At least the break will give us time. It's a ligament thing, he was playing with it and it started to get a bit worse."