"Dane is having a few problems with his knee too - he can't seem to straighten it," Hansen said. "He's gone back to the surgeon and the surgeon has put him back in a brace at night to try to help him get full extension.
"Once that happens he'll make progress pretty quickly. He is unlikely to be available for June."
Both men are among the best in the world in their positions but of the two Read may be the more difficult for Hansen to replace for the French series, which starts at Eden Park on June 9.
Highlander Liam Squire is an obvious replacement but has a broken thumb and could lack game time when he returns, while veteran Jerome Kaino, off to France at the end of the season, is out for six weeks with a torn hamstring.
Luke Whitelock, the Highlanders No8, and Blues loose forward Akira Ioane are now likely to be in the All Black mix.
As far as the No2 jersey goes, Codie Taylor has been in good form for the Crusaders, with Nathan Harris of the Chiefs and Asafo Aumua likely to be his back-up for the black jersey.
Hansen, a constant presence at New Zealand derbies recently, said he was pleased with the form of the men he was keeping an eye on, adding: "A lot of younger players are putting their hands up as well.
"A lot of teams are battling their way through some heartache and others look like they're doing it pretty easy. It's interesting watching how everyone's coping with that but by and large the people we need to be playing well are playing well."
Hansen said his "foundation days" – short camps educating those in the All Black frame before the French series – were working well. Those North Island players in the mix for the national team will meet in Wellington next Monday before more physical "preparation camps" will be held in Auckland on May 20-22 and Christchurch on May 27-29.
"We've got a lot of work done that we won't have to do nearer to game time. We won't have to fill them with words, we'll be able to actually do stuff and prepare for the test match properly."
To get the day's top sports stories in your inbox, sign up to our newsletter here