Thieves broke into a storage locker on Tuesday and made off with a quad-runner, used by the team's mascot, Thunder.
"We've never really had a problem with this before so it is an isolated incident for the most part. I don't know if they knew what was back there or not, but they found the quad," said the stadium's director of ticketing, J.T. Onyett.
Team officials believe the thieves cut the lock to the shed, hotwired the bright green quad and drove off, leaving behind a few foot prints and not much else, much to Thunder's devastation.
The all-terrain vehicle is used as part of Thunder's grand entrance onto the field during home games. It's off season, so there is still time to track down the 2003 Kawasaki, valued between $2,000 and $3,000.
"April 4, the Padres are playing here, so we're hoping for that major league game we can have Thunder be Thunder and come out on his quad," Onyett said.
While mascots are known for pulling pranks, team officials said this is no stunt.
"With all the press we've been getting for it, maybe we should have done it, but we did not. This is not a publicity stunt at all," Onyett said.
Anyone with information is asked to contact the Riverside County Sheriff's Department at (951) 776-1099. The team is also offering a reward, which includes season tickets to its games.