"Some players need a breather because they have had two international games as well as Champions League and Premier League games recently. They will have played five games in two weeks," explained Wenger.
Arshavin has made three substitute appearances this month but has started only one game -- the 6-1 defeat of Coventry City in the third round of this competition -- this season.
"Andrei is a classy player," Wenger said. "He is a top professional with a great attitude. You could see when he came on last Saturday. His brightness and his intelligence with the final ball is fantastic."
"Of course you want players who've had less time in recent weeks to get on the field of play," said O'Neill. "But the most important issue is to win. It's a tough call."