Gillespie, 74, guided UCI to a fifth-place finish at the College World Series after a dynamic and unexpected postseason run helped him garner National Collegiate Baseball Writers Assn. Coach of the Year honors.
Izzi elected not to announce the length of the contract, which has yet to be signed, but did say that a handshake agreement is in place. Izzi also said he would have had Gillespie back, even if UCI had not made the NCAA Tournament. Gillespie's current contract expired at the end of this season.
The Anteaters (41-25), were one of the final four teams admitted to the 64-team NCAA Tournament field this season after losing their final eight Big West Conference games to fall from first to third in the standings and fall out of the national top-25 polls.
UCI defeated No. 1 national seed Oregon State twice to win the Corvallis Regional, then swept Oklahoma State, ranked No. 10 in the final Baseball America poll, to advance to Omaha for the second time in the program's Division I history.
UCI, ranked No. 8 in the Collegiate Baseball poll that followed the super regionals, defeated Texas, 3-1, before falling to Vanderbilt, 6-4, and Texas, 1-0, to bow out of the double-elimination CWS, at TD Ameritrade Park.
Gillespie's 27th season as a Division I head coach, his seventh at UCI, included his 1,000-th career Division I victory.
Gillespie, who guided USC to the 1998 NCAA championship and also played for a national championship team as a Trojan, has coached teams to 20 postseason berths, including five College World Series appearances.
Inducted in 2010 into the American Baseball Coaches Assn. Hall of Fame, Gillespie led UCI to super regionals in 2008 and 2011 and led the 2009 team to the program's lone Big West title and the No. 1 national ranking. He is 1,037-615-2 overall, including 20 seasons at USC, and 274-144 at UCI.
UCI had missed the postseason the previous two seasons and, with only a handful of proven players returning, was not expected to halt that streak this year.