Kansas City, Mo. ? The last time the Kansas City Chiefs had a winless preseason, they went 7-9 and fired their coach.

Maybe it’s a good thing Dick Vermeil already was thinking about this being his final year. A succession of tough breaks, positive drug tests and punishing league edicts is threatening to overwhelm a much-

heralded overhaul of the defense and make an 0-4 exhibition campaign the least of his worries.

Cornerback Eric Warfield and offensive lineman John Welbourn are suspended for the first four games, Warfield for violation of the NFL’s substance abuse program and Welbourn for a steroid violation which Vermeil does not believe he was guilty of.

Jonathan Quinn, their quarterback for almost all of the last two exhibition games, was cast aside on cutdown day. Trent Green, their starting quarterback, has had vascular surgery to repair a torn artery and is on blood thinners. He took only about 60 percent of his normal preseason snaps.

The entire offense, slowed by injuries, aches and pains, was way behind schedule as today’s opener against the New York Jets drew near.

Yes, there are five new starters, four on a defense which figures to be significantly upgraded from the sadsack unit that finished 31st overall and 32nd against the pass.

But Green, the most indispensable starter on the roster, played only one full series in the third exhibition game. Because doctors did not want him to fly, he didn’t even make the trip to St. Louis for last Friday night’s game.

“Trent only ended up playing 56 snaps this (preseason). We would have liked to have him play 75 to 85 snaps with the work he missed only practicing once a day,” Vermeil said. “I’m confident we can catch up, but I’m not sure how long it takes. We haven’t been as efficient, other than the opening drive against Seattle.”

In their busiest offseason in years, the Chiefs poured all their energy and a big chunk of their money into defense. It made sense. For three years running, one of the NFL’s elite offensive machines had been neutralized by a pitiable defense which had not risen higher than 29th.

But their best player in training camp and the preseason was third-year running back Larry Johnson, who seems ready to step out of the shadow of three-time Pro Bowler Priest Holmes. If things get straightened out at quarterback, success could hinge on how well the Chiefs exploit the talents of both the accomplished veteran and the frisky youngster, and if they can keep them both happy.

“I don’t know if there’s a scientific way to do it,” Vermeil said.