Having a keeper not playing shouldn't be a concern because you just sub in the reserve and that doesn't really matter because keepers very rarely get dropped/rested so assuming your 2nd keeper is currently in the side and not injured/suspended no problem. It's not like outfield players where you need to worry about having too many inactive players on the bench.
Personally if I had 3 outfield players not playing I'd be looking to use my 1-2 FT to provide a bit of cover, for example Giroud is worth about £8.3m last I checked so I'd be looking to transfer him out for a new striker given that he isn't playing this week, has an illness and potentially some doubt over whether he will start even when he comes back (bearing in mind he was benched against Reading with Wenger experimenting with Walcott through the middle).