Vikings work on troubling red-zone defense before facing Kansas City

Vikings coach Mike Zimmer made red-zone defense a point of emphasis when his players returned to practice this week after a long weekend to savor a four-game win streak and a 6-2 record at the halfway point of the season.

“We had to put some extra work in there,” said Zimmer, whose team travels to Kansas City on Sunday with a red-zone defense on pace to rank outside the top three for the first time since 2016.

The Chiefs aren’t dominating in the red zone offensively. They rank 25th in touchdown percentage (.481), but the Vikings rank 15th in touchdown percentage allowed (.550) after ranking third both last year (.449) and in 2017 (.400), when they also ranked first in goal-to-go situations…