Due to the new number system it is difficult to accept team sheets emailed in with names on. If you know you'll be missing weeks in advance and are not making any transfers (therefore not changing your squads numbers) you can pick your teams in advance with their numbers and send it in.
If you are making transfers (therefore changing your numbers of your squad) you can either try to work out what the new numbering will be with your new players in, or get someone on the game to send in the team sheet for you.