ZURICH – Led by the league's top goal-scoring duo, the Colorado Rapids snapped a four-year playoff drought in 2010 and ultimately claimed their first MLS title.
Cummings scored a career-best 14 goals last season to finish tied for fourth in the league. Casey had 13 and scored twice during his team's playoff run, including the tying goal in the MLS championship game against FC Dallas.
Injuries have played a big role in the two strikers being limited to a combined six goals this season. Since Cummings and Casey both started the season opener, the only other time this year they have been on the field together was the second half of a 3-1 loss to Los Angeles on June 18.
That defeat started Colorado's current three-game winless stretch (0-1-2), during which it has been outscored 7-2.
"I'm still disappointed that we're not putting the goals up," defender Drew Moor told the league's website. "You can't win games if you don't score goals ... We definitely have the firepower and the individuals to do that, and that'll come."
The Rapids (5-5-8) have been limited to 11 goals in 15 games since scoring eight during a franchise-best 3-0 start. Cummings scored twice in that streak, but a sprained right ankle kept him out of the starting lineup for two months until Sunday's scoreless draw against Houston.
Casey, who missed six games earlier this season because of a strained left hamstring, was serving a suspension for receiving a red card during a June 26 loss at Columbus.
"We just can't seem to get everything in place," coach Gary Smith said. "It will come together. It's going to come together."
Smith's club has the daunting task of facing a team that is 4-0-4 in its last eight. Plus, the Rapids are 0-7-3 at Kansas City since winning there Sept. 14, 2002.
Sporting KC (5-6-5) is 1-0-2 in the last three overall matchups and kicked off its current unbeaten stretch with a 1-all draw at Colorado on May 28.
It overcame the absence of captain Davy Arnaud (hernia surgery) to record its second straight win Saturday, 2-1 in Portland. C.J. Sapong and Auerlien Collin gave their team all the scoring it would need in the first 19 minutes.
"I think it's just confidence," defender Matt Besler said. "During the 10-game stretch that we had on the road (to start the season), we thought we were playing well but things just weren't going our way.
After traveling for 13 of its first 16 games, Kansas City will play 11 of 12 at Livestrong Sporting Park, where it's 2-0-1. Remaining unbeaten there Wednesday would give the team its longest overall unbeaten streak since a 6-0-3 run June 5-July 24, 2004.