Brian McDermott has confirmed that Danny Guthrie asked not to be considered for selection ahead of Reading's trip to Sunderland on Tuesday.
Guthrie, 25, has endured a difficult start to his Royals career amid rumours in October of a training ground rift with McDermott - something that was vehemently denied by his manager at the time.
However, when asked why the former Liverpool trainee had not made the trip for his side's 3-0 loss to the Black Cats, McDermott admitted it was Guthrie's decision.
"Danny Guthrie made a decision that his head wasn't right to travel," he said. "Everyone's got to be going in the same direction and that's really important for me as a group and we've had that over a period of time.
"You have to put yourself up to be selected each and every time and that means every player. His words were his head wasn't right. He would have been travelling.
"Any player has to be a part of what we're about, we can't deviate from what we've been about over the last three years. We're very much about the group, we have to be and we all have to pull in the same direction. It's something we need to address in the week."
Guthrie has made only five appearances for Reading in the Premier League this season and is now unlikely to be selected for Arsenal's visit on Monday night.