Another yellow card would lead to a one-game suspension for United midfielder/forward Dwayne De Rosario. (Ned Dishman/GETTY IMAGES)

Where: Rio Tinto Stadium, Sandy, Utah.

When: 9 p.m.

TV: Comcast SportsNet.

Radio: WDCN (87.7 FM, Spanish).

Records: United 12-9-5, 41 points; Real Salt Lake 13-10-4, 43.

D.C. probable starters: GK Bill Hamid; Ds Andy Najar, Dejan Jakovic, Brandon McDonald, Chris Korb; MFs Nick DeLeon, Perry Kitchen, Marcelo Saragosa, Chris Pontius; Fs Dwayne De Rosario, Lionard Pajoy.

RSL probable starters: GK Nick Rimando; Ds Tony Beltran, Kwame Watson-Siriboe, Nat Borchers, Chris Wingert; MFs Ned Grabavoy, Kyle Beckerman, Javier Morales, Will Johnson; Fs Fabian Espindola, Alvaro Saborio.

Preview: United, which is playing the last of five matches in a two-week span, has lost its seemingly comfortable spot in the MLS playoff chase. The top five teams in the Eastern Conference will advance to postseason, which is still two months away. D.C. is tied with the Chicago Fire for fourth place at 41 points but has played one additional match. The Montreal Impact (three more games than United) and Columbus Crew (one fewer) have 39 points. United has lost five straight and six of seven on the road, and is seeking its first win in Utah since 2005, RSL’s inaugural season. Since then, United is 0-5-1 with four goals scored and 14 conceded. MF-F Chris Pontius has scored 10 goals, while F-MF Dwayne De Rosario has seven goals and 12 assists, tied for second in MLS. RSL, among MLS’s preseason favorites, is third in the Western Conference, seven points behind the San Jose Earthquakes and level with Seattle but has played two more matches than the Sounders. Coach Jason Kreis’s squad is in a 0-3-1 rut and drew at Philadelphia eight days ago. F Alvaro Saborio has scored 14 goals, tied for second behind San Jose’s Chris Wondolowski (18). This is the only regular season meeting between the clubs, who are 5-5-4 all-time against each other. Last year, De Rosario recorded a first-half hat trick against Real at RFK Stadium. He must be cautious: With a yellow card, he will surpass the MLS limit and earn a one-game suspension.

— Steven Goff