NHL referees won't have to scan cavernous Ohio Stadium to find a clock during Saturday's Stadium Series game between Detroit and Columbus. They'll just have to feel the vibrations on their wrist.

The NHL, Apple and Presidio have created a system for real-time, in-game situational notifications with the NHL Watch Comms App, which runs on Apple Watches specifically configured for on-ice NHL officials. Officials are alerted by haptics to time ticking down at the end of a period and the end of power plays.

While referees and linespersons have been using the Apple Watch software throughout the 2024-25 season, this weekend marks the first time it will be used in an NHL outdoor game. The Red Wings and Blue Jackets face off at 6 p.m. ET Saturday at Ohio State's football stadium.

Stephen Walkom, the NHL's executive vice president of hockey operations, was an on-ice official for three decades. He said this technology is an important innovation.

"You were always searching to find the clock, and every rink's just a little bit different. While you were doing that, you were taking your eyes off the ice," he said. "In the stadium games, it was even harder. You're staring off into space looking for a clock and a guy gets hooked on a breakaway. For us, this is a dependable, durable and useful tool to keep us safe and focused on the game."

The NHL's relationship with Apple tracks back to 2017, when iPads were first placed on every bench so real-time video of plays could be available for viewing. Dave Lehanski, NHL executive vice president of business development and innovation, said that after coaches and players were given that technology, the league's attention turned to how to make its officials' jobs easier.

Andres de Corral, vice president of digital services and solutions at Presidio, said the software provides three main functions. It displays the game clock and jersey numbers of players in the penalty box. It has a running penalty timer, sending vibrations to the official's wrist when a power play is about to end.

"They have a 200-pound person flying at them at 50 mph," Corral said. "We want to make sure they're out of the way and not necessarily get tripped up. That was really the key for official safety."

Walkom remembers that from his days as an NHL referee.

"We had a number of near misses. You're trying to avoid each other, trying to keep up with the pace of the play, and you've got to know that the guy's coming out of the box," he said. "But getting that little notice, that warning at 10 seconds, it makes you aware where you need to be to stay out of the way of the player."

The watch also alerts officials to the clock ticking down for the end of a period, with haptic notifications for 10, 3, 2 and 1 seconds left "just so they could really ensure their eyes are on the ice and the players," Corral said.

The penalty box and game clock haptics are different vibrations.

Rather than using the scoreboard clock as a reference, the watches pull 25 data points from the NHL's OASIS feed, which is part of the league's NHL Edge puck and player tracking system. Pulling the data, rather than using push notifications, dramatically decreased the lag between what's happening on the ice and what's delivered to the watch. Instead of relying on an arena or stadium Wi-Fi, the watches use cellular connectivity.

The NHL Watch Comms App was launched in September 2024. The league said 92.5% of on-ice NHL officials have adopted wearing the Apple Watch. Walkom said those who haven't were waiting on customization of their watch bands.

The league is already considering other ways to use this technology to help its on-ice officials.

Part of the NHL Edge system tracks the "stick and limb" movements of players during the game. Lehanski said that data isn't publicly available yet because "we're still authenticating for accuracy and for consistency from arena to arena."

Once the NHL is satisfied with its accuracy, the NHL Watch Comms App might be able to alert an official that a puck had been contacted by a high stick.

"You could have a time where you measure every player on normal heights of the shoulder and you get a notification when that particular player touches the puck with a stick above their normal height to the shoulder," Walkom said. "You get it instantly. It's not a judgment call."

There has also been discussion about whether the watches could eventually alert officials to pucks getting shot into the netting behind the goals, which is something that occasionally misses detection on the ice. In time, as the NHL's puck tracking continues to be refined, Lehanski hopes the watches could one day alert referees that the puck has crossed the goal line if their sightlines are blocked.

The watches could also create more connectivity for all the officials watching the game.

"All of this speaks to the future potential for how we leverage the watches potentially for communication. Thinking about the officials on the ice, the other officials in the arena, the officials that are in the video review room in Toronto and maybe leveraging that as a component down the road," Lehanski said. "No doubt we're just scratching the surface."