The Frenchman, who signed for the Trotters in the summer, was unable to secure regular first-team football during his three seasons at Anfield, making a total of 21 starts in his time at the club.
"That's probably a question to ask David," Clarke told the side's official website, when asked whether he will be out to prove a point. "He's certainly got nothing to prove to us.
"He was at Liverpool a long time, he came here as a developing player and he's showing that he's developed into a good Premier League player.
"It was David's choice. He wanted to go and try something different and Liverpool were good enough to let him go."
Meanwhile, N'Gog admitted earlier this week that it would be "special" to score against his former club.