Marcus Rashford
Marcus Rashford trains with his England U21 teammates at St George's Park in Burton Alex Livesey/Getty Images

Gareth Southgate has spoken positively regarding Marcus Rashford's impact on the England U21 set-up, but knows that a positive showing could see him return to the senior team sooner rather than later. The 18-year-old striker has already earned three full caps for his country after a breakout 2015/16 campaign for Manchester United, yet is in line to make his first appearance at U21 level this evening (6 September) in a 2017 Uefa European Championship qualifying Group 9 match against Norway at the Weston Homes Community Stadium.

"It is difficult to have a plan," Southgate told BBC Sport of his international future. "The leaps can be so quick and you are never sure when it is going to happen. We know exactly where we are this week. Moving forward depends on how they play with their clubs and what injuries there might be and the performance of the senior team as well."

Praising Rashford's performances in training, he added: "You would think he had been with us for a longer period of time. That is testimony to the mentality he has arrived here with."

Rashford's surprisingly seamless transition to first-team football was a shining light in an otherwise largely gloomy final season under Louis van Gaal at Old Trafford, with the academy graduate announcing his arrival with back-to-back braces against FC Midtjylland and Arsenal in February.

He scored a total of eight goals in his first 18 outings towards the end of the year, an impressive haul that prompted Roy Hodgson to give him a shot at winning a place in his squad for Euro 2016.

Despite only having a handful of previous youth appearances to his name, Rashford made the most of his chance and broke Tommy Lawton's 78-year record as the youngest England player ever to score on his senior debut as he notched after less than three minutes of a narrow friendly victory over Australia at the Stadium of Light. That was enough to secure his place in France, where he made a positive impact as a second-half substitute in the last-gasp win over Wales but came on too late to help prevent that embarrassing last-16 exit at the hands of Iceland in Nice.

Rashford has been used sparingly during the early stages of Jose Mourinho's United reign, left on the bench for consecutive top-flight wins over Bournemouth and Southampton after playing a bit-part role in the Community Shield win over Leicester. Having been named in the U21 squad to face Norway, which Southgate insists is not a demotion but rather a beneficial experience towards his goal of appearing at the 2018 World Cup in Russia, he responded two days later with an an eye-catching cameo against Hull City in which he scored a last-gasp winner.

England boss Sam Allardyce and assistant Sammy Lee will be watching from the stands in Colchester and it is hard to think that an impressive display from Rashford coupled with an improved role under Mourinho will not help earn a quick recall to the senior fold following that largely tedious late win against Slovakia in Trnava on Sunday.