The Chelsea defender reiterated boss Fabio Capello's claims that the Red Devils frontman is concentrating on the Euro 2012 qualifier despite discovering his father and uncle had been arrested over a betting probe.
"Wayne's focused on the game tomorrow," Terry said in a press conference. "As I said before it's important for him to go out and play football. He's always focused on the football field and that's all that matters for us."
Chelsea and England midfielder Lampard has faced criticism after being omitted from recent international and club matches.
"At times you do get left out and it tests your character and I think [Lampard] has proved all of his critics wrong," Terry said.
"He's scored some great goals but his performances have been just as good."
Meanwhile, the 30-year-old believes that the younger members of the squad will not be daunted by the prospect of getting their first cap.
"When the guys first come in the squad you make them feel welcome," he added. "But they are very assured of themselves that if they do get the opportunity tomorrow they'll give a very good performance."
England only need one point to qualify for the next stage of the European Championship.