Given made himself available this week to play for the Republic of Ireland again after announcing his retirement in the aftermath of the European Championships.
And Lambert believes the veteran is still playing well enough to represent his country.
He said: "If that's Shay's thinking, then fine. For me, the way he's trained and the way he's played in the games has been excellent.
"He is no doubt good enough to come back and play for Ireland and has played well in the Capital One Cup matches.
"I'm just fortunate to have two such fine keepers available to choose from."