Long made a shock return home after Saturday’s loss at the hands of New Zealand, sparking speculation that he had been sent home for some disciplinary reason or another; while the Great Britain management cited personal reasons.
"After Saturday I realised I was physically and mentally fatigued and had nothing more to contribute," Long explained in his own words for the first time.
"While I feel I've let the team down, I honestly feel I'd have let them down further by trying to play again."
Long was instrumental in the Lions’ 23-12 win over Australia a fortnight ago and picked up the man of the match report, but looked distinctly out of sorts against New Zealand in the record 34-4 defeat.
Coach Brian Noble has announced that Long will be replaced by Richard Horne for this week’s vital game, from which Great Britain need a win or at least a draw to progress to the Tri-Nations final.
However, Noble admitted that long would have been selected had he still been with the squad, saying: "He would definitely have started had he still been here.”
"But when you have moving personal issues you have to deal with those and respect his thought processes."