Sam Warburton is expected to be given three warm-up games to prove his fitness to face the All Blacks after being told by medical staff he cannot play for Cardiff Blues again this season.
The 28-year-old Wales flanker, who could become only the third player in history to captain the British & Irish Lions in successive series when they take on the world champions next month, suffered a knee ligament strain playing for the Blues against Ulster in April.
Lions coach Warren Gatland named Warburton as his tour captain a week later, despite fears over his fitness.
It was hoped early on that Warburton could feature for the Blues in their end-of-season play-off push for a place in the Champions Cup, the Daily Mail reported.
The flanker's injury has been closely monitored by Wales and Lions head of medicine Prav Mathema, with Warburton understood to have been eager to play for the Blues before leaving for New Zealand at the end of this month.
Gatland said earlier this month: 'Sam feels he could play now. He has made some really good progress and is really happy with how he has responded to treatment over the last few weeks. I expect him to play before he goes to New Zealand.'
But, despite the early optimism, the decision has been taken to hold the Lions captain back from any competitive action until the start of the 10-match tour, which kicks off against New Zealand Provincial Barbarians on June 3.
"The medical staff are very happy with Sam's progress but they will not risk him aggravating the injury before the start of the tour," a well-placed Lions source told Sportsmail.
"His recovery is going really well but the risk associated with him playing for the Blues is considered too high for him to take a chance.
"There have been some mixed messages about whether he will play for the Blues again this season. But to be clear, he definitely will not."
Warburton's absence will be a major blow for Blues supporters who had hoped he would feature in their European Cup play-off against Stade Francais on Friday.
But it may be a sensible move to ensure he has every chance of being fit for what is expected to be a gruelling and attritional Test series in New Zealand.