Grimble is the fifth Trojans starter to opt to leave before his eligibility is over, joining receiver Marqise Lee, safety Dion Bailey, center Marcus Martin and defensive lineman George Uko. The Trojans still have two scholarship tight ends in senior-to-be Randall Telfer and junior-to-be Jalen Cope-Fitzpatrick.
The Davis hire obviously means that Ed Orgeron, the Trojans' former interim head coach after the firing of Lane Kiffin, won't be returning. He resigned when Sarkisian was hired, but Sarkisian said he would make another run at hiring Orgeron, a specialist with defensive linemen and one of the nation's top recruiters.
Davis spent the past three seasons coaching the defensive tackles at Texas under Mack Brown. Before going to Texas, he spent eight of the previous nine years on Nick Saban's staffs at Alabama, LSU and the Miami Dolphins.
Sarkisian retained two members of USC's 2013 staff -- receivers coach Tee Martin and offensive coordinator Clay Helton -- and brought in five members of his former staff at Washington. Davis and offensive line coach Tim Drevno, formerly of the San Francisco 49ers, were the only outside hires.
Here's how Sarkisian's nine-man staff stacks up:
Clay Helton, offensive coordinator/quarterbacks
Justin Wilcox, defensive coordinator
Johnny Nansen, running backs/special teams coordinator
Tee Martin, receivers
Tim Drevno, offensive line/running game coordinator
Marques Tuiasosopo, tight ends/associate head coach offense
Bo Davis, defensive line
Peter Sirmon, linebackers/recruiting coordinator
Keith Heyward, defensive backs