Bannan, called up into the Scotland squad, returned to the Villa starting XI to help them achieve back-to-back wins over Reading and QPR.
Lambert said: "No one is happy when they are left out and that will never change. But I had a chat with Barry and he has responded in a really good way.
"You need everyone pulling in the same way. They are all as important as each other.
"This has been Barry's first season of being in the first team for long periods, then being taken out and being in and out.
"Sometimes you need to do that to young players, take them out and give them a break, and then put them back in and get the impetus from that."
Bannan earned his Scotland call-up after West Brom midfielder James Morrison withdrew with a hamstring injury.
Aston Villa last week