By Chris Harris
Both players were last seen limping off during Premier League games at Emirates Stadium - Bendtner against Tottenham on October 31 and Rosicky against Stoke City on December 5.
The Czech midfielder's groin injury has taken just three weeks to heal but Bendtner will have to wait longer to shake off his own groin problem. The Danish striker was earmarked for a comeback early in the New Year but that target has now been revised to mid-January.
Arsène Wenger explained why when he spoke to reporters ahead of the trip to Portsmouth.
"Rosicky I would say will be fit for Portsmouth or for West Ham [in the FA Cup on Sunday]. But Bendtner is three weeks away from returning," said the manager.
"He had a hernia surgery and should be back from that already but he had a groin problem as well.
"The groin problem looks to last longer so they [the medical staff] say to me it will be three weeks."
Wenger is also waiting for news of Cesc Fabregas' fitness after he hobbled off with a hamstring problem against Aston Villa on Sunday.