The 30-year-old Todd, who has committed to New Zealand rugby for 2019, had initially been considered unavailable for the end-of-season tour after signing up with Panasonic Wild Knights and was not named in this year's Rugby Championship squad.
However, with Sam Cane ruled out until next year after sustaining a broken bone in his neck against South Africa, Hansen's options at openside flanker are limited with Ardie Savea the only other player with test experience at the position available for the tour.
Hansen decided to seek dispensation from New Zealand Rugby for Todd to be selected for the tour, while the uncapped Dalton Papail'i was also named in the squad.
"There's been no change of heart," Hansen told reporters in Christchurch when asked about Todd's selection. "He's committed to New Zealand rugby. He's very much in the mix for next year's World Cup.
"We went to the board and requested that we use him with the understanding that he will be coming back to the Crusaders and is contracted to them until the end of 2019.
"They thankfully agreed and Panasonic have been kind enough to agree with us also.
"We just really saw him as being on a holiday, and we've asked him to come back from holiday."
Todd will only be eligible for selection for the third Bledisloe Cup clash with Australia in Yokohama on Oct. 27 as well as games against England and Ireland.
He will miss the games against Japan on Nov. 3 and the final clash with Italy.
"The reason we've gone for Matty is because we need some serious experience to back Ardie up in the three big tests, against Australia, Ireland, and England," Hansen added.
"That was our thinking. Some people may disagree with it, but I think most people will see he's worthy of being there."
Hansen also said that Shannon Frizell, who was in the Rugby Championship squad, had suffered a shoulder injury and needed to rest. The 24-year-old would not need surgery, he added.
Jordan Taufua, who was named in the squad for the June series against France but later ruled out with injury before breaking his arm in Super Rugby, was not considered as he would not be fully fit until the middle of November.
(Reporting by Greg Stutchbury; Editing by Peter Rutherford)
