Arizona Diamondbacks coach Ariel Prieto says it was a mistake for him to wear an Apple Watch in the dugout during the National League wild-card game against the Colorado Rockies.

Prieto told reporters on Thursday that he didn't use the watch for any illicit purpose and that it was on "airplane mode" during the game, a setting that shuts off any of the watch's communication abilities. The former big league pitcher is an extra coach who also serves as interpreter for the Diamondbacks.

Last month, the Boston Red Sox were fined by Major League Baseball for using an Apple Watch to relay signs to hitters.

Prieto said he knows having the phone during the game violated MLB's rules. He said he apologized to manager Torey Lovullo and volunteered to turn the phone over to MLB officials.