The Gunners take on Manchester United at Old Trafford on Sunday.
The Gunners have been struggling in front of goal in recent weeks, with the midweek loss to Barcelona in the Champions League a clear demonstration of that.
Giroud in particular seems to have lost his goal-scoring touch, having now failed to score in his last eight games, the worst form of his Arsenal career.
And Nicholas says the Frenchman’s stuttering form is the main concern he has about his old side at present, as they gear up to take on Manchester United on Sunday.
“My biggest concern right now is Olivier Giroud,” he told Soccer Saturday.
“I think when he got a bit of criticism then came in to replace Theo Walcott, he was competitive again which was good. But I thought against Barcelona you could have taken him off and you wouldn’t have noticed the difference.”
“You’re centre forward for Arsenal becomes like the goalkeeper, the most important ingredient to go and win this title.”
With Giroud continuing to struggle, perhaps Arsene Wenger will now drop the Frenchman and go with a different option up front.
That is likely to be Theo Walcott, who has been given his chance in a central role this season and impressed doing so earlier in the campaign.
His pace could be a real threat up against a particularly slow United defence, and it would not be surprising to see Wenger make that particular selection choice in Sunday’s big clash.