This latest injury has prompted retired Auckland neurosurgeon Philip Wrightson to advise the Crusaders star to coinsider quitting the game for at least a season - if not for good.
"The real problem is if you suffer a second concussion," Wrightson said. "I have always felt if you suffer a second concussion you should give up playing for the season. If, in the next season, you have another concussion, you should think very carefully about giving up the game."
MacDonald said that while he would listen carefully to all medical advice, he would be taking advice from the All Blacks' medical staff, who would consult specialists. He had total faith in long-serving All Black doctor John Mayhew.
MacDonald expected a decision would be made this week on his immediate future. It would be "a mutual decision" between himself, the medical staff and the All Black coaches. The All Black management have said MacDonald would be given all the time he needed to recover fully.
"I still have a lot of rugby left in me. MacDonald said. "There's still a World Cup to try to aim for. The All Black squad for that is probably the biggest priority."