The academy is currently tied to his only club until the summer of 2015 but Agbonlahor, now 27, is hoping to extend his 15-year stay at Villa for longer after breaking into the first team in 2006 at the age of 19.
Although contracted to the end of next season, Agbonlahor is already thinking of signing another extension to take him into his 30s, and potentially to the end of his career.
When asked about Agbonlahor being a one-club player, Lambert said: "It's pretty rare now. There aren't too many around.
"I know Gabby has been here a long time, and when you look at the next 20 months that's also a long time in football.
"In years gone by you wouldn't find out what was happening to you until a week before the end of the season.
"Then all of a sudden it goes full circle and it becomes 20 months, two years (prior to the end of a contract when a player signs a new deal). It's just strange in football.
"I understand what he is saying, but there is a long, long way to go before there's anything on that. The end of season is the time to look at these sort of things."
Agbonlahor said: "It is hard in this league to be a one-club man, but it's always been on my mind to play for Villa until I retire.
"It feels weird even thinking about putting another shirt on. The club has high hopes and we are building the squad. Look at the facilities, fan base, Villa Park and the training ground - there's no reason why you would want to leave."
Agbonlahor has set his focus on adding to the 295 senior appearances he has made for the midlands outfit and closing on Gareth Barry's club record of 440 Premier League outings.
The England international added: "I'm here for another year-and-a-half, equalling Gareth Barry's record doesn't really bother me. It's more about keeping my place in the side, keeping playing for Aston Villa and if I get longer than him then that would be good.
"A lot of players move on but for me it's about working hard and achieving things with Villa, and hopefully I can stay at the club.
"The club has got high hopes and we are building the squad. Look at facilities, fanbase, Villa Park and the training ground, there's no reason why you would want to leave.
"If you look at the teams we've beaten on our day, if we get the right bit of luck and the team plays together, then we can do well. It shows there are good things happening."