Wenger won't gamble with Van Persie

Holland striker Van Persie returned to action against Steaua Bucharest in midweek following almost two months out with a knee problem.

Wenger said: "At the moment, Robin does not have the green light medically. Once he gets that, we have to test him on the pitch with the other players and then we can make a decision."

While the seven-goal forward looked sharp against the Romanians the 24-year-old is the first to admit he is short of match fitness, completing just over an hour on Wednesday night.

And with injury concerns over Cesc Fabregas, Mathieu Flamini and Alex Hleb, Wenger knows not to expect too much, too soon heading into the top-of-the-table showdown at Emirates Stadium.

He said: "They are practising, but not with the team. They are not in normal training.

"Who will come back into normal training before Sunday? It could be one, two or three.

"It is too early to say, and the selection will depend on that because you can gamble on one or two - but not five."

The Gunners hold a slender one-point lead over Manchester United heading into this weekend's fixtures, which also sees the Red Devils head to Liverpool on Sunday lunchtime.

Victory for Chelsea, themselves on an impressive 16-match unbeaten run, would move them level with their opponents.