The France international was pictured driving into the club's Carrington training ground this morning but was seen leaving shortly afterwards.
However, after initial fears Martial had picked up an injury, the Manchester Evening news confirmed the Frenchman had arrived for training at the wrong time.
Martial was said to have turned up at Carrington at 8.56am before leaving at 9am after he was informed training was later in the day.
His mishap is unlikely to affect his participation in Saturday's visit of Brighton to Old Trafford, after making his return to the first-team picture.
The 27-year-old appeared to have put his injury hell behind him after starting the Red Devils' last two fixtures.
Read more on Man United
Young: Ibrahimovic fought and picked on Man United teammate but it was all love
Manr United star Rashford left dumbfounded by EA FC rating - 'Am I that bad?'
Martial lined up for United in the 3-2 win over Nottingham Forest last month before playing his part in the 3-1 defeat at Arsenal, eventually being replaced by new £72million signing Rasmus Hojlund.
Last-gasp heartbreak at the Emirates has seen United lose both of their away games this season and Ten Hag will expect his side to return to winning ways this weekend.
However, Brighton will be plotting a second-consecutive league win at Old Trafford after comfortably seeing off Newcastle 3-1, last time out.
Ten Hag's side will need to find momentum with a huge clash against Bayern Munich in the Champions League looming.
Most read in Football
Maguire's mum hits back at abuse, critics branded 'sheep', forgotten Spurs duo make squad
Young: Ibrahimovic fought and picked on Man United teammate but it was all love
Man United star Rashford left dumbfounded by EA FC rating - 'Am I that bad?'
Harry Maguire's mum issues heartfelt statement questioning abuse aimed at her son
United's two wins, both coming at Old Trafford, have been far from convincing after limping over the line against Wolves in a 1-0 win on the opening weekend of the season.
That was followed by a 3-2 win over Nottingham Forest after falling two-goals behind after just four minutes.
Martial is expected to fall down the pecking order this season following Hojlund's return to full fitness.
United were prepared to listen to offers for the Frenchman this summer who has failed to convince despite entering his ninth season at the club.
But keeping hold of Martial will give Ten Hag much-needed cover to launch an assault of all competitions this season.