Lampard has been in and out of the Chelsea side since Villas-Boas took over as manager last summer. Villas-Boas was recently accused of blanking Lampard on the team bus following the midfielder's failure to join in a goal celebration with the Chelsea boss during last week's Premier League win at Wolves.
Villas-Boas, though, dismissed reports which suggest Lampard could leave the club in January, despite the England international being linked with Manchester United.
"We speak every day," Villas-Boas said. "Frank is a player who is not available at any price.
"First, he's not in and out in rotation. There is no such thing. We decide on an XI who are strong for any game and that can help us in the strategy to win the game.
"Every player wants to find that consistency and playing times. Frank, with the player he is and the history he represents, wants to be involved all the time, but every player is competing for a place.
"I've said the same all season, even when Frank had more playing time and others didn't. Everyone is fighting to be in it, and a player of Frank's level has a shorter distance to travel to be in the team than others."
Lampard has been dropped for all of Chelsea's big games recently but Villas-Boas insisted this did not mean his powers were on the wane.
"Players have different characteristics and your strategy depends on how you want to play the game," he said.
"Other players might be better placed in certain games, or players might be in better form than others.
We try different options at times, but Frank is the fifth or sixth most used player at Chelsea so he's involved all the time. We are speaking of two players ahead of him. One is a goalkeeper and the other is John Terry."
Part of Lampard's frustration stems from the knowledge the clock is ticking on his playing career. Villas-Boas refused to put a timescale on the midfielder's eventual departure, suggesting the player himself would know when the time was right.
"You have to respect players of this magnitude who have reached lots of success," he said.
"Players know more or less what the competition is around them and make the necessary judgments to see who is overtaking them. An up front relationship would see them inform the manager and we would make the best decision possible."