The ball sailed high and deep toward the post, where Washington Redskins receiver Rashad Ross and Atlanta Falcons cornerback Robert Alford were running and jostling for position.

Ross had a step to the inside. Alford was close behind, eyes on the ball. His right hand touched Ross' back. His left hand brushed the right shoulder as he reached for an interception. Ross used his right arm to ward him off.

Then: Ross fell, the ball hit the ground and the flags flew. Referee Bill Vinovich's crew tagged Alford with defensive pass interference (DPI), a 42-yard penalty that put the Redskins in position to take a fourth-quarter lead Sunday at the Georgia Dome. It was a borderline call but an explosive, potentially game-changing play for which the Falcons had no recourse -- a reminder that DPI is the most damaging penalty in football.

Officials call other penalties more frequently, but as the chart below shows, none impact a team more on a per-call basis than DPI. Through the first month of this season, in fact, the average DPI penalty cost defenses 17.3 yards. Coaches cannot challenge the decisions because, like all penalties considered to be judgment calls, it is not a reviewable play in the NFL's replay system.

On this day, let's ask why. The precedent, as it turns out, already has been set north of the border.

Yes, the CFL added DPI to its replay system at the start of the 2014 season. Remarkably, the league did not go out of business. In fact, the process has worked so well after some early struggles that league officials hope to include offensive pass interference and illegal contact in 2016, according to CFL vice president of officiating Glen Johnson.

"What it takes," Johnson said via phone this week, "is patience."

A missed illegal bat call during Week 4 renewed calls to extend the reach of NFL replay, but as I pointed out at the time, there is little appetite among owners and league officials to usurp key judgment decisions from on-field personnel. (Last spring, NFL executive vice president Troy Vincent floated the idea of limiting DPI penalty yardage to 15 yards regardless of the throw distance.)

Johnson faced the same challenge in the CFL until settling on a universal standard for imposing a judgment decision. CFL coaches can challenge a DPI call, or ask that a play be reviewed for the potential of calling one, until the three-minute mark of either half. Replay officials watch first at full speed and then slow motion with a simple question in mind.

"What we're asking is this: 'Did we miss a clear pass interference call or did our official make a call that clearly wasn't there?'" Johnson said. "We're not trying to find a needle in a haystack and decide if this hand tugged a little bit or that arm might have pushed. In the replay center, we're trying to fix the ones that are obviously wrong. That's the mentality we found we had to have."

Initially, Johnson acknowledged, officials struggled to find that balance. In 2014 postgame reviews, Johnson found that he disagreed with about 15 percent of the replay decisions. This season, however, the CFL pegs its review accuracy rate on DPI at about 92 percent, nearly 50 percent better than the first season.

"That's about as good as it gets in professional sports officiating," Johnson said. "No one is perfect, but these are very important penalties and we need to do everything we can to get them right."

The NFL standard for pass interference, either on offense or defense, is laid out clearly in its rule book. Rule 8, Section 5, Article 1 says: "It is pass interference by either team when any act by a player more than one yard beyond the line of scrimmage significantly hinders an eligible player's opportunity to catch the ball."

The rule goes on to specify seven acts that can constitute pass interference, among them grabbing an arm or using contact to cut off the path of an opponent without playing the ball. There are also five permissible acts that include "incidental contact" and "inadvertent tangling of feet."

What is "significant" and what is "incidental" or "inadvertent"? The NFL wants on-field officials to make those judgments, no matter how difficult they might be in real time. The CFL has found what it considers a workable safety net. It's worth further examination.