Alvarez, Wisconsin's athletic director, will coach the Badgers in the Outback Bowl against Auburn on Jan. 1. He is replacing Gary Andersen, who abruptly left the program Wednesday to become Oregon State's coach.
Alvarez said Thursday a number of seniors asked him to consider coaching the team in the game.
"The last 24 hours have been hectic to say the least," Alvarez said. "It's been somewhat overwhelming but fun. I'm honored the players asked me and we're going to get ready to play against a good team."
Alvarez said he was waiting for a flight at LaGuardia Airport in New York when Andersen told him of his plans to leave. The AD said the players asked him to coach Wednesday after meeting with Andersen and he said he would think about it, but they pressed him again Thursday morning.
"I just couldn't tell those kids no," Alvarez added. "It bothers me that the kids have to go through this. Change is difficult for them."
Alvarez coached the Badgers for 16 years before taking the athletic director's job. He retired following a 24-10 victory against Auburn in the 2006 Capital One Bowl. He was pressed back into service to coach the Badgers in a loss to Stanford in the 2013 Rose Bowl after Bret Bielema surprised players by leaving to take the Arkansas job.
Tony Sanchez, who won six consecutive Nevada state titles at Bishop Gorman High, was hired as coach at Nevada Las Vegas. Sanchez, 40, went 85-5 at Bishop Gorman and did not lose against another school from Nevada.
Sanchez is believed to be the fourth coach to make the direct jump from high school to major college head coach, joining North Texas' Todd Dodge, Notre Dame's Gerry Faust and Iowa's Bob Commings.
Tulsa hired Baylor offensive coordinator Philip Montgomery as its head coach. Montgomery has been calling the plays for one of the most prolific offenses in college football for the last four seasons. Baylor is the only major college team to be ranked in the top two in the country in total offense each of the last four seasons and the top four in the scoring offense over that same time.