Portsmouth No2 Tony Adams admits he knows the true reason why Lassana Diarra quit Arsenal earlier this season - but won't be letting on.

"I know why Arsene [Wenger] let him go but I'm not going to say," said Adams with reference to the Arsenal manager's £5.5m sale of Diarra five months after paying £2m to take him from Chelsea. "Have you asked Lassana?"

Diarra has maintained that he left the Emirates Stadium because he was frustrated at his lack of playing opportunities in the countdown to Euro 2008 with France and knew that Portsmouth could offer him the pitch time he craved.

"You have to think outside the box," advised Adams.