Ex-Arsenal star Frank McLintock admits Arsenal are heavily reliant on the fitness of star striker Olivier Giroud.
Speaking to talkSPORT, McLintock said he'd been hugely impressed by the Gunners so far this season.
But the ex-Arsenal centre-back is concerned at the club's reliance on French international Giroud.
"When you think of the Aston Villa game at the start of the season, we were all complaining about what is wrong with the club, and yet they have been unbeaten since then and looked very good as well," McLintock told talkSPORT.
"My primary concern is if all of a sudden our centre-forward Giroud gets injured, we will be seriously in trouble. There is no one there.
"[Theo] Walcott could occasionally play there but I don't think he is comfortable there."
Since the Aston Villa home defeat, Arsenal have won three Premier League games on the bounce - with Giroud on target four times through four matches.
But with Lukas Podolski and Yaya Sanogo currently sidelined, the former-Montpellier star is Arsenal's only recognised option through the middle for the time being.
They made it six straight victories in all competitions last night, with a hard-fought 2-1 win over Marseille in their first Champions League group stage match.
Giroud returned to the south of France but didn't get on the scoresheet - the Arsenal goals were scored by Walcott and the in-form Aaron Ramsey.