The weapon turned out to be a replica firearm, said police department spokesman Cmdr. Andrew Smith. The boy was transported to a local hospital and released after treatment.
"It's certainly an unfortunate situation," Smith said. "But because of people bringing replica weapons out like that, it certainly could have been a terrible tragedy."
Around 7:45 a.m. Tuesday, two officers were driving in the 7200 block of 10th Avenue when they spotted a group in an alley. A teenager was pointing what police thought was a gun at another person, Smith said.
Officers ordered the boy to drop the weapon multiple times, Smith said. When he didn't comply, one of the officers opened fire.
The teen holding the replica weapon was unharmed, but the 15-year-old boy standing next to him was struck, Smith said.
The officers detained everyone present and concluded the group were friends. "No animus" was involved, Smith said.
No arrests were made.
The person holding the replica weapon could potentially face charges of brandishing a replica weapon in the presence of a police officer, but investigators were still discussing that option with prosecutors, Smith said.
The names of the officers involved are expected to be released after the department's initial 72-hour briefing. The officers have been removed from the field pending the department's initial review.