Sometimes the space between winning and losing in the NFL is so thin that light can’t shine through. If the Cardinals don’t understand that after last Sunday’s 13-10 loss to the Seahawks, they never will. NFL power rankings – Week 4 | Top football games to watchThe Cardinals left Seattle believing they did a thorough job of beating themselves. That was the lament of several players in the locker room at CenturyLink Field.The season is young, but the refrains have become familiar already: The Cardinals left plays on the field. It’s a different guy every play. They’re still getting to know each other and the system.Judging by a handful of critical offensive mistakes Sunday, there is truth in those statements. Let’s break down one of the miscues as best as possible, given that coaches and players aren’t going to reveal exact play calls and assignments.The Cardinals trailed 13-10 in the fourth quarter and had moved to the Seattle 33, where they faced third and 13. They needed to gain around 5 yards to give kicker Jay Feely a better chance to make a field goal into the wind.In the huddle, quarterback Kevin Kolb called the play. As part of the package, Kolb let everyone know that if the Seahawks appeared to be bringing pressure Kolb would “check” to another play: a quick screen to receiver Andre Roberts, flanked to the right.Sure enough, Kolb sensed pressure from a safety and changed the play. That’s when things fell apart.Kolb threw quickly to Roberts, who should have had a couple of blockers in front of him. Instead, Roberts was on his own and cornerback Marcus Trufant tackled Roberts for a 2-yard gain. Feely’s 49-yard attempt into the wind was well short, and Seattle still led, 13-10.So what went wrong? “First of all, the personnel was not correct,” coach Ken Whisenhunt said. “We weren’t lined up correctly. We’re asking a guy to do something he hasn’t had a rep (repetition) on. If we didn’t have the alignment error, then we probably do get the check because the guy that’s normally in that position understands what he’s looking for. So it’s kind of a snowball effect.”As is his custom, Whisenhunt refused to assign blame. Looking at video of the play, it appears tight end Todd Heap was the one who made the mistake. He was in the middle of three receivers lined up to the right on that play, with Early Doucet on the inside.Heap ran a crossing route across the middle, away from the screen, while Doucet tried in vain to get outside quickly enough to help Roberts.Matching Whisenhunt’s comments with the replay, it appears Heap either should have been lined up in Doucet’s spot, or at the very least, understood that the audible meant he had to block for Roberts.Even with the mistake, Roberts had room if he had cut inside. Instead, he danced a bit and was tackled.Heap played a good game, otherwise, catching six passes for 61 yards and surviving a vicious block in the first half.That mistake on third and 13 wasn’t the only difficult play for the Cardinals to watch on Monday. Guard Daryn Colledge, who signed as a free agent in July, missed a blitz pickup that disrupted a potential big play. So did rookie fullback Anthony Sherman. The Cardinals converted just one of nine third-down chances in the second half.And the final opportunity of the game came with a minute left, when Kolb tried to force a pass to Heap at the Seattle 25. Kam Chancellor intercepted. Replays showed both Roberts and Doucet running free on shallower routes.It was third and 12 at the Seattle 36. Again, the Cardinals needed just eight to 10 yards to get within Feely’s range on a windy day.Of course, there are plays in every football game that miss by the width of a baby’s fingernail, but the Cardinals think they are missing an inordinate amount because they have so many new players in critical roles.On the bright side, Whisenhunt said, there are plays to be made. The Cardinals hope they can start making them before they’re buried by mistakes.