Leonard, who replaces Tawera Kerr-Barlow, and Smith, named in the reserves, have not played since the first-round loss to the Highlanders due to respective hamstring and calf problems.
Flanker Tanerau Latimer and wing Tim Nanai-Williams start ahead of Sam Cane and Asaeli Tikoirotuma respectively and hooker Hika Elliot starts ahead of Mo Schwalger.
The Chiefs, the competition leaders having won their last seven matches, are playing New Zealand opposition for the first time since their victory over the Crusaders in round three. The Hurricanes go into the match following their thrashing in Wellington at the hands of the Crusaders.
The match will be co-captain Craig Clarke's 50th for the Chiefs.
Coach Dave Rennie said: "It has been a demanding three weeks. We know it is going to be a tough encounter against the Hurricanes this weekend, they will be grumpy and have a few of their key players coming back so it will be a hard battle.''
Chiefs team to play the Hurricanes at Waikato Stadium on Saturday, kick-off 7.35pm, is: Andrew Horrell, Lelia Masaga, Richard Kahui, Sonny Bill Williams, Tim Nanai-Williams, Aaron Cruden, Brendon Leonard; Alex Bradley, Tanerau Latimer, Liam Messam, Brodie Retallick, Craig Clarke (c), Ben Tameifuna, Hika Elliot, Sona Taumalolo. Reserves: Mo Schwalger, Toby Smith, Michael Fitzgerald, Sam Cane, Augustine Palu, Jackson Willison, Asaeli Tikoirotuma.
