The only holdup on an immediate official announcement is the assembly of a staff, according to ESPN:
Sources said that Brown has offered Illinois State coach Tim Jankovich a "coach-in-waiting position." Jankovich is leaning toward accepting the job, but he's also conflicted about leaving a Redbirds squad that returns every key player from last season's 21-14 team.
Brown has been out of basketball for just under two years, when he left the NBA's Charlotte Bobcats in 2010. He's the only basketball coach in history to have both a NCAA Championship (Kansas, 1988) and a NBA title (Detroit, 2003).
For more on Larry Brown and the SMU Mustangs, go to SB Nation's college basketball page.