Manchester United resume club action with an away trip to newly promoted Southampton but two other competitions will begin soon too, opening up playing opportunities for youngsters. Carabao Cup begins on September 17 with a home game vs Barnsley, with Europa League starting soon after on September 25. READ MORE: Premier League 24/25: Man Utd Fixtures, Start Date, Schedule, International Breaks & MoreThe league remains the bread and butter, however, especially after two losses in the first three games. Therefore, with injury problems already rearing their ugly head this soon into the season, Er…