Jose Mourinho has clarified c will start for Manchester United in their Champions League group stage opener against Young Boys on Wednesday.
Shaw did not travel with the squad for United's 2-1 Premier League win at Watford on Saturday as he recovered from concussion sustained in England's defeat to Spain at Wembley earlier this month. Mourinho said Shaw was not considered for selection since he had hardly trained during the week.
Young replaced Shaw against Watford and played a pivotal role in United's narrow victory at Vicarage Road, where two of his set-pieces resulted in goals for Romelu Lukaku and Chris Smalling.
Shaw, 23, is 10 years younger than Young and has enjoyed a superb start to the campaign. Mourinho stressed that the resurgent Shaw will be recalled in Bern.
"Luke Shaw plays Wednesday," Mourinho said. "We can't do it with one left-back and Ashley Young is not just a left-back, is also a right-back, they both are doing well and they both are different players.
"And I think both understand one is a young player and the other one is the experienced one and is good for us to have these two options and Darmian is my emergency man, is always ready for everything, so we are fine."
Marouane Fellaini was instrumental as United scored twice from set-pieces where Young pinged aerial balls to the Belgian at the far post. Mourinho was particularly delighted United's dead-ball prowess proved decisive since they had been practising the tactic in training.
"Because we trained the corner during the week, the best thing that can happen to coaches is you train and you see it happen in the match," Mourinho beamed. "And they are happening even in these last few matches, even in the one against Tottenham, are happening things that are working, the positional, the movement.
"But the set-pieces are very specific things that you work, you work, you work and for weeks and weeks and weeks sometimes you don't see the results of that work. So when it happens was happiness for coaching staff."