His two missed attempts in Sunday's road loss to the Buffalo Bills at New Era Field, which was played in a snowstorm, put him below the mark.
The 44-year-old special teams ace said afterward that footing was the toughest factor as snow continued to pile up on the field throughout the contest.
"Trying to run through snow and get good plant, that's crazy," Vinatieri said. "If it was just snow and no wind, it's one thing. But you get both of them. It was a tough game."
Although he missed both field-goal attempts, he did convert his only extra point when the Colts tied the game with a late touchdown. The kick, which started well right of the goal posts, took a major left hook in the wind to level the score at 7-7. Buffalo won on a LeSean McCoy touchdown run in overtime.
Last year, Vinatieri missed a 48-yard field goal in the first half of the Colts' final game that cost him the same $500,000 bonus.
"I'm not a big stats guy. I've said it many times in my career that every kick counts," he told reporters in January. "I missed it by a kick. Had I made one earlier in the season, it wouldn't have been an issue. Would have been nice to hit it, but I didn't."
Getting back to 90 percent will require him to make his next five kicks. Another miss would virtually cut his chances completely, since he would need to connect on nearly every attempt over the next three games to reach 90 percent again.