MacDonald is still battling to overcome his latest bout of concussion, and coach Graham Henry said team management were loathe to place him at risk.
That means he will not be considered for the test against Samoa in New Plymouth next Wednesday or for the Tri-Nations decider against Australia in Brisbane on September 13.
MacDonald has been sidelined since being concussed during the All Blacks' 28-30 loss to the Springboks in Dunedin on July 12.
He missed the following tests against the Wallabies and South Africa and has not appeared at Air NZ Cup level for Canterbury.
Henry said there continued to be concerns about MacDonald's recovery.
"I think Leon is still struggling," Henry told Radio Sport today.
"He probably will not be available for the next two test matches."
Henry said MacDonald was being closely monitored by medical personnel.
"The doctors are keeping a close eye on him."
MacDonald, 30 and the veteran of 56 tests, has a long history of concussion since he made his first-class debut 11 seasons ago, with a series of head knocks in 2002-03 prompting a break from the sport.
