The 19-year-old striking sensation was dropped by new manager Sam Allardyce for today's qualifier against Slovakia – the first match of his regime.
But Under-21 manager Gareth Southgate said: “To be part of the squad that goes to Russia should be his target – along with other players I have with me.
“It is not a demotion to be with the Under-21s, not at all. It is a chance for him to start matches.
“It was the same with Juan Mata in Spain. We have had players over the years who have been in both squads, so there is no reason why Marcus should not carry on his development with us."