Arsenal defender Hector Bellerin has pulled out of Spain’s Under-21 squad with injury.
The full-back is believed to have aggravated an ankle knock picked up in Sunday’s north London derby with Tottenham.
The news will concern Gunners boss Arsene Wenger, coming 10 days before the trip to face Manchester United.
Bellerin’s withdrawal was confirmed on Twitter by the Spanish Football Federation, with Sunderland’s Javier Manquillo called up as a replacement for the European Under-21 Championship play-off games with Austria.
It is the second injury scare this week for Arsenal, after Alexis Sanchez suffered a “low grade muscle injury” while training with Chile.
He will definitely miss their World Cup qualifier in Colombia on Thursday but has not yet been ruled out for the home game against Uruguay next Tuesday.
Lucas Perez (ankle) and long-term absentees Danny Welbeck and Per Mertesacker will definitely miss the Old Trafford game, while Santi Cazorla (Achilles) is a doubt.
After that game, Arsenal have three home matches in a row. They face Paris St-Germain in the Champions League on 23 November and then host Bournemouth in the Premier League and Southampton in the League Cup.