Hurricanes flanker Masoe and Chiefs lock Kevin O'Neill have been added to the All Black squad for the Tri-Nations test against the Springboks in Wellington on Saturday.
Masoe replaces injured captain Richie McCaw for at least the first two tests in the competition, while O'Neill is added as cover for Ali Williams, whose sprained ankle is not quite as severe.
The surprise choice of O'Neill will be a blow to Donnelly's hopes of graduating to the international ranks.
O'Neill (26), who emerged in Canterbury before transferring to Waikato, had a quiet Super 14 and seems far from international class.
Donnelly, in contrast, has had four consistent years with the Highlanders and would add specialist skill to a misfiring line-out.
Donnelly now looks likely to be available for Otago for the duration of the Air New Zealand Cup, where he will do as much as he can to get on the plane for the Grand Slam tour in November.
Masoe was a regular in the All Blacks from 2005 to 2007, earning 20 test caps - most off the bench - in all three loose forward positions.
This year the All Black selectors started playing a left-right combination that suited players with more mobility than Masoe.
Now, with two tests in eight days approaching against the rugged Springboks, they like what he offers physically.
"Chris' experience against South Africa and knowledge of our systems mean he's the right choice," All Blacks coach Graham Henry said yesterday.
"But we may want to take a different approach against Australia. We'll look at form and fitness and the team's plan again in a couple of weeks."
The starting All Black side will be named tomorrow, with most expecting a recall for Jerome Kaino at No 8 and Rodney So'oialo and Otago's Adam Thomson playing on the flanks.
Williams will soon be back.
"The medical staff is reasonably positive that Ali will be available this weekend, but it is sensible to have extra cover just in case," Henry said.
He also confirmed So'oialo would be the All Blacks captain in McCaw's absence.
McCaw suffered a serious ankle injury during the All Blacks' 44-12 win against England in Christchurch on June 21, ruling him out of action for an expected six weeks.
New Zealand's second test against South Africa is in Dunedin on July 12.
