Wayne Rooney will miss Manchester United's match against FC Midtjylland in the Europa League on Thursday.
Rooney did not board the flight to Herning, having not been named in the 18-man travelling squad for the first leg of the round-of-32 tie.
The club did not explain the forward's absence but said manager Louis van Gaal is set to address the matter at his news conference at the MCH Arena, scheduled for 5 p.m. GMT on Wednesday.
The United captain has scored seven goals in nine appearances since the start of the calendar year.
- Manchester United (@ManUtd) February 17, 2016
United are facing a busy schedule due to their Europa League commitments. Thursday's first leg in Denmark is followed by a trip to Shrewsbury in the FA Cup on Monday. United will host Midtjylland on the following Thursday, then there is a Sunday game when Arsenal visit Old Trafford in the Premier League.
They will also be without full-back Matteo Damian for the trip to Denmark, with the Italy international having dislocated his shoulder during Saturday's 2-1 defeat at Sunderland.
Marouane Fellaini was rested for the loss at the Stadium of Light and he was again left out of the squad for the FC Midtjylland trip. The Belgium midfielder had started seven games in a row before his recent absence. Adnan Januzaj, meanwhile, is cup-tied after featuring for Borussia Dortmund in the competition while on loan there.
Donald Love, the 21-year-old right-back who made his first-team debut at Sunderland, is included, as is forward Will Keane. Three players who could make their first senior appearance -- defender Regan Poole, wing-back Joe Riley and midfielder James Weir -- are also in the squad.
Squad: De Gea, Romero, Love, McNair, Smalling, Blind, Poole, Riley, Carrick, Herrera, Schneiderlin, Lingard, Pereira, Weir, Mata, Memphis, Martial, Keane.