With United manager Ole Gunnar Solskjaer set to name a handful of youngsters in the XI that starts at Stamford Bridge, Greenwood might have been expected to be involved.
Fellow teenagers James Garner and Brandon Williams are both tipped to start against Chelsea and made the trip down to London with the senior squad, but Greenwood was left out of the travelling group so that he could face Doncaster Rovers.
United’s junior team secured progress from the group stage to the next round of the competition, with Greenwood himself scoring a 94th minute winner at the Keepmoat Stadium. The youngsters had already beaten Rotherham and Lincoln senior sides earlier this season.
Tahith Chong captained the Under-21 side in South Yorkshire, but there was no Angel Gomes in the squad. Emerging right-back Ethan Laird, who was on the bench for the Europa League game against Partizan last week, also played.
Greenwood may have been expected to play some part for the senior side due to their lack of depth up front and Anthony Martial only recently returning to fitness.
There were no other major surprises in the 18-man first-team squad for the Chelsea clash. As is often the case, the group travelled to London by train, with the Manchester Evening News there to record those who were ready to board.
David de Gea is expected to sit this one out, with Sergio Romero and Lee Grant the only goalkeepers making the journey. There is no Paul Pogba, who could now be missing until December because of injury, while Luke Shaw remains absent.
Manchester United's 18-Man Squad for their Carabao Cup 4th Round vs Chelsea:
Goalkeepers: Sergio Romero, Lee Grant
Defenders: Phil Jones, Victor Lindelof, Harry Maguire, Marcos Rojo, Aaron Wan-Bissaka, Brandon Williams, Ashley Young
Midfielders: Fred, James Garner, Jesse Lingard, Juan Mata, Scott McTominay, Andreas Pereira
Forwards: Daniel James, Anthony Martial, Marcus Rashford
For more from Jamie Spencer, follow him on Twitter and Facebook!
Source : 90min