With Lukas Podolski out with a severe hamstring injury, the Gunners are left with just Olivier Giroud in the strikers position and Parlour suggests that is not enough for a team to challenge for the title.
"I'm worried about the forward line," Parlour told The Daily Star. "Giroud was excellent against Spurs (in the 1-0 North London derby win).
"It's the only position I am worried about. If Giroud does get hurt, they are going to be light.
"They got (Mesut) Ozil in - great. But could they have signed a striker as well?"