Fletcher, the conference's player of the year, injured his knee earlier in the tournament, and the senior was forced to leave Friday's semifinal in the first minute. The Rockets rallied without him and beat Eastern Michigan 64-63.
Toledo was seeking its first NCAA appearance since 1980 on Saturday night, but the Rockets couldn't earn it without Fletcher, who is averaging 18.1 rebounds, 8.0 rebounds and 4.3 assists.
In the semifinal, Toledo freshman guard Marreon Jackson hit a game-winning 3-pointer with nine seconds left to send the Rockets into their first conference final since 2014. Jackson, a Cleveland-area kid, made a school record eight 3s and finished with 26 points.
Buffalo won its third title in four years. The Bulls were the tourney's top seed for the first time in school history.