Kansas City, Mo. ? Sure, it’s only the preseason, and sure, preseason wins and losses are as meaningless in the NFL as last month’s weather report.

That doesn’t mean the Kansas City Chiefs do not need very much to play well tonight against St. Louis. In fact, the Chiefs all agree that this could be an especially important night in many ways.

In a summer of transition, they’ve looked awful in preseason losses at Houston and the New York Giants. Kansas City is breaking in a new head coach, a new offensive coordinator and several defensive assistants, while attempting to implement a fresh approach to both offense and defense.

It’s time to play well and gain some confidence.

“The players understand that; the coaches understand that,” said head coach Herm Edwards. “And I think they’re going to go do it.”

It will be the first preseason home game for the Chiefs (0-2) and Edwards’ first appearance in Arrowhead Stadium as their head coach. For the Rams (1-1), it will be their first preseason game on the road under new head coach Scott Linehan.

Missouri’s two NFL teams have much in common. Both are operating under new head coaches and both are attempting to tone down explosive offenses while giving new emphasis to defense.

Edwards replaced Dick Vermeil, whose offense the past five years passed for more yards (20,117) and touchdowns (111) than anybody but Peyton Manning.

Gone from the Rams is Mike Martz, architect of the “greatest show on turf” that carried St. Louis to a pair of Super Bowls. Now Linehan is busily putting in two-tight end sets, insisting on quick, shorter pass routes and placing more emphasis on a ball-control ground game.

And that is almost exactly what Edwards and new offensive coordinator Mike Solari are trying to do with Kansas City.

But although the first-team offense has seen limited action the first two games, it has not been particularly impressive. One reason may be the unsettled look of the offensive line. Left tackle Willie Roaf abruptly retired, left guard Brian Waters missed most of camp and right guard Will Shields has an ankle injury that will sideline him tonight.

“We need to get some rhythm obviously, but the only way you can open it up is to stay on the field,” Edwards said. “The last two games we haven’t done a good enough job of that.”

Out of 21 possessions the first two games, the first team offense had 12 drives in which they were three-and-out.

“You can’t get any rhythm on offense doing that,” Edwards said. “So we need to get out early, get some plays, and that’s been some of our problem.”

The regulars, including running back Larry Johnson and quarterback Trent Green, will play more this week, at least well into the second quarter.

Also making his debut will be defensive end Tamba Hali, the first-round pick out of Penn State who has been hobbled with sore ribs.

“It’ll be interesting to watch him play and see how he’ll react in his first game,” Edwards said. “He kind of timed it out pretty good, missed all of camp, and comes home for the opener and gets to play. Hope he doesn’t exhaust himself after three plays and hyperventilate.”

While the players are working hard to keep their focus on the game, Edwards could be excused for letting his own mind wander at least a bit. Lia Edwards is expecting their third child and could deliver as early as Sunday.