Leinart will be placed on season-ending injured reserve after fracturing his left collarbone during the second quarter of Houston's 20-13 win at Jacksonville on Sunday.
Kubiak said Monday that Leinart will have surgery within the next week, and Schaub is due to have surgery Wednesday to repair a Lisfranc injury.
Kubiak also said the Texans will try out other quarterbacks this week and hinted that 42-year-old Favre, who retired in January after 20 NFL seasons, could be considered.
"I don't think you rule out anybody," Kubiak said when specifically asked about Favre. "There are a lot of names being mentioned. We've got to continue to work through the process.
"I'm not going to rule out anybody, nor confirm anybody."
Favre's agent, Bus Cook, said late Monday the Texans haven't contacted him about Favre.
Despite losing one key player after another, Houston (8-3) has won a franchise-record five consecutive games. Rookie T.J. Yates, a fifth-round draft pick out of North Carolina, will start Sunday's game against the Atlanta Falcons. Kellen Clemens, signed last week, will back him up.
Copyright 2011 by The Associated Press