Our weekly attempt to expose and explore the gray area involved in officiating NFL games. Sunday suggestions welcome via Twitter (@SeifertESPN). For all Inside Slant posts, including the weekly Officiating Review, follow this link.

Plays: Replay upholds a fumble by New Orleans Saints tight end Jimmy Graham and a non-touchdown by Minnesota Vikings tight end Chase Ford

Referees: John Parry and Tony Corrente

Analysis: These plays are grouped together because they hinge on the same concept, one we've discussed several times already this season. The NFL has raised its standard for overturning calls on replay reviews, using the "indisputable visual evidence" requirement more literally than ever.

In New Orleans, Graham appeared close to scoring on the first play of the fourth quarter. A touchdown would have turned a 20-7 deficit into a one-score game, but Parry's crew ruled that Graham fumbled and did not cross the goal line first. The play was key to the Saints' 30-14 loss, one that eliminated them from playoff contention.

We got a true goal-line angle on the replay, and it was reasonable to guess that, in the likeliest scenario, the ball crossed the plane in Graham's possession. But the ball was partially obscured by Graham's right arm, and by the right arm of Atlanta Falcons safety Kemal Ishmael as he began stripping it. We never got a 100 percent clear view -- "indisputable visual evidence" -- that a touchdown occurred.

In Miami, Ford caught a 22-yard pass down the right sideline and carried it into the end zone before he was tackled. Corrente's crew, which included field judge Gary Cavaletto at the pylon, ruled Ford's right foot had stepped out of bounds at the 1-yard line, before the score. A close look at replay in slow motion revealed what appeared to be a strip of green between Ford's shoe and the sideline, suggesting he had remained in bounds.

The strip was thin, however. Did Ford step on a blade or two of white grass? Reasonable people could guess that he probably didn't, but that doesn't meet the replay standard the NFL is pursuing. Remember what vice president of officiating Dean Blandino said earlier this year: "We have a ruling on the field. If it's not clear and obvious that that ruling on the field is incorrect, the call will not be overturned."

Per NFL statistics, successful coaches' challenges are down from 52.4 percent last season to 40.2 percent in 2014. Booth reviews are overturning 33.5 percent of calls, down from 37.1 last season. The reduction is by design.

Play: Pittsburgh Steelers cornerback William Gay penalized for taunting

Referee: Ronald Torbert

Analysis: This episode occurred after Steelers linebacker Lawrence Timmons tackled Kansas City Chiefs tight end Travis Kelce for a 2-yard gain on third down, presumably forcing a punt. Kelce got up and began walking back toward his sideline, while Timmons scrambled from a prone position near the Steelers' sideline.

Gay had arrived a moment before, stopping about 2 yards away from where the tackle occurred. About 7 yards away, side judge Scott Edwards was running toward the middle of the field with his hand up to signal the end of the play. Standing still and facing Timmons, Gay folded his arms in a standard -- and very old-school, I might add -- celebration aimed at his teammate. Kelce was moving in the opposite direction, and both he and Gay would have had to turn their heads 45 degrees to their left to see one another.

Replays show Edwards turning his head over his right shoulder as he continued running. He saw Gay's pose, stopped and threw the flag. It was only the second taunting penalty Torbert's crew had called this season.

It's possible Edwards heard penalty-prompting language from Gay. Otherwise, it would seem he mistook Gay's celebration -- directed at Timmons -- for a taunt aimed at Kelce. If you wonder how that could happen, take a quick jog, swing a glance to your right and then try to remember the details of what you saw.

The NFL instructed officials to pay special attention to taunting during games this season, but through Week 16, a modest 22 such penalties had been called. (Competition committee co-chair Jeff Fisher said in March: "We're going to clean the game up on the field between the players. The in-your-face taunting. The language.")

Did that instruction prompt Edwards' call? Perhaps. Either way, it appears to have been a major gaffe in a game with direct playoff implications. The Chiefs got renewed life on a fourth-quarter possession that resulted in a field goal that reduced their deficit to one score.

Play: Cleveland Browns defensive linemen Billy Winn is ruled to have given himself up after an interception

Referee: Ed Hochuli

Analysis: In the third quarter, Winn made a diving interception at the 44-yard line of an errant pass by Carolina Panthers quarterback Cam Newton. Winn rolled over on his back and handed the ball to teammate Jordan Poyer, who ran into the end zone.

Why wasn't this play a touchdown? After all, no Panthers player touched Winn before he handed off the ball. Hochuli announced that Winn was "ruled down, gave himself up on the ground."

Via Rule 7, Section 2, Article 1(d), the NFL rulebook provides two ways for a player to declare himself down. One is to slide feet first. The other is by "falling to the ground, or kneeling, and clearly making no immediate effort to advance."

Winn didn't slide feet first. But did he fall to the ground and "clearly" make no "immediate effort to advance?" Common sense should prevail here.

Diving for the ball led Winn naturally to roll over. He didn't do it as smoothly as a wide receiver, but that might be because he is a 300-pound lineman. The moment he reached his back, he looked up and saw Poyer standing over him.

It's true that Winn didn't make "an immediate effort to advance," but that was because he was in the process of handing the ball to Poyer. During the transfer, Winn remained on his back. This interpretation suggests the only way Winn could have made the transfer was to do it while (or after) he got up off the ground. In this instance, a strict reading of the rulebook led to a counterintuitive ruling in reality.