Crusaders skipper McCaw would lead the All Blacks on their end-of-season tour to Europe for Tests against Scotland, Italy, Wales and England, but would then take a break from the game in a bid to prolong his career, Fairfax media quoted Blackadder as saying in comments published on Sunday.
"It is definitely going to happen," Blackadder said. "He will probably be available after June. He won't be available for the tests or Super Rugby, so he's going to get a good break.
"We've worked this through with all parties and I fully support it.
"He had it written into his contract and he's elected to take it... It will freshen him up and he'll come back and be good for the next couple of years."
The 31-year-old McCaw's uncompromising play and fierce attack at the breakdown has taken its toll in recent years.
The openside flanker, regarded as one of the world's finest in the position, was sidelined for much of last year's Super Rugby competition and carried a painful foot injury into the All Blacks' successful bid for a second World Cup title in 2011.
After undergoing surgery, McCaw returned in April to lead the Crusaders into a semi-final appearance in the 2012 Super Rugby season and has returned to top form for the All Blacks in the current southern hemisphere Rugby Championship against Australia, South Africa and Argentina.
Like New Zealand flyhalf Dan Carter, McCaw extended his contract with the New Zealand Rugby Union until 2015, with the option to take a sabbatical from the game offered as a sweetener for forgoing more lucrative contracts offered overseas.
New Zealand generally selects only NZRU-contracted players for the national side, effectively locking out players who head overseas to play in foreign leagues.
A Crusaders spokesperson said McCaw's sabbatical had been agreed in principle but the start date and the exact amount of time off had yet to be determined.
"Richie is smart enough to know what his body needs," All Blacks coach Steve Hansen said.
"If we want to get him through to the (2015) World Cup, it's a good idea. The Super 15 is a tough competition. For someone like Richie to step out of that, he obviously thinks it's pertinent, hence why it's in his contract."
McCaw will lead the All Blacks on tour to Argentina and South Africa as they seek to clinch the inaugural Rugby Championship trophy with a win over the Pumas in La Plata on Saturday.
The All Blacks close out their tournament against the Springboks in Johannesburg the following week before playing a test against the Wallabies in Brisbane on October 20.
The world champions then head to Europe for November tests against Scotland, Italy and Wales, before finishing the season-ending tour against England on December 1.
- Super Rugby