By the end of the week, he could potentially have two more.
Surprisingly enough, it's the two schools closest to his Orange County (Calif.) home who have yet to offer him a scholarship. But Costello remains confident after strong performances in front of both staffs that a Bruin and Trojan offer could be on the way.
"This week I'll be getting on the phone with [UCLA quarterbacks] Coach [Taylor] Mazzone – so we'll see how that goes," Costello said after participating in the Bruins Elite Camp. He doesn't have a time frame in mind for when he feels UCLA could extend an offer, but said he felt it was important to show interest in the Bruins, doing so by participating at their camp.
"It's definitely a school that I'd love the possibility to go to or the opportunity to go to," he said.
The week prior to camping with the Bruins, the Scout four-star threw at USC's skills camp with Trojan quarterbacks coach Clay Helton alongside a group of other high school quarterbacks.
"I kind of feel like it went really well," Costello explained. "I sat down with Coach Helton and [head coach Steve] Sarkisian. They're waiting for a couple other quarterbacks to come in at Rising Stars (June 24-25) before they make their decision – so that's kind of where that sits."
The Southern California native says he is open to the possibility of moving away from home to attend a school and play in a program he feels fits him best. He recently went on an East Coast swing with a stop in the Midwest to check out a few different programs.
"I went on a like a six school tour - Florida State, Florida, Tennessee, Alabama, Michigan. It was important for me to get out because obviously USC and UCLA are a big attraction for me," said Costello. "But I definitely want to get out and see that big time football in the SEC and the environment.
"It's pretty incredible, so it was well worth the trip."
Despite his positive remarks about his trip across the country, it seems likely that an offer from USC or UCLA could potentially put either program in the lead of his recruitment.
"I've been watching them my whole life," Costello said. "I've been to probably every USC and UCLA game for the past seven years. I'm definitely not favoring one side or the other. Both are right in my backyard and I would love to have the opportunity to go them."