One game on the right isn't going to kill him.
That isn't really the issue. He could play there personally at least I don't see what he'd bring to the position. His game isn't about taking people on and he isn't really that quick. I don't even see him as an improvement over Osman for the RW.
Rodwell got a lot of time last year as people were injured. He isn't a better DM than Fellaini, or for that matter Heitinga and he isn't a creative replacement to Arteta. He'll get his chances this year but it has to make sense, when the aforementioned players aren't doing the job or the they need a rest or are injured.