During the preseason, the NFL experimented with a high-tech system for measuring first downs, but that system will be shelved during the regular season in favor of old-fashioned chains.

The NFL will not use the Hawk-Eye computer vision system in the regular season this year, but could try it out in 2025, according to Mark Maske of the WashingtonPost.

Although Hawk-Eye represents a tremendous innovation in tennis, where it is used to determine whether a ball was in or out of bounds, it did not work so well in the preseason to detect first downs. Most notably, it was used for Postponement of the preseason game between the Lions and the Giants when the high-tech system took much longer than the conventional chains to achieve the necessary performance on a play that was not even close to a first down.

In tennis, it’s easy for Hawk-Eye to use camera angles that allow a clear view of the ball relative to the line. In football, it’s much more difficult: sometimes players block the cameras’ view of the ball. Sometimes the ball is clearly visible, but not whether the ball carrier’s knee was down before the ball crossed the line. Unlike in tennis, the line doesn’t actually run on the court, so it’s not always clear at what point the ball crossed the line.

It’s entirely possible that the technology will one day be used in the NFL. But that day won’t be in 2024.