2:55 p.m. at Portland • ESPN, 1500-AM

Preview: United can clinch a playoff spot for the first time in its three MLS seasons with a victory Sunday, thanks to Atlanta's late 3-1 victory over San Jose on Saturday. It remains aimed at a home playoff game as well that goes to Western Conference teams that finish second, third or fourth when the regular season ends Oct. 6. … The two teams play for the third time since Aug. 4. United beat the Timbers 1-0 that day at Allianz Field on Ethan Finlay's penalty kick converted in second-half stoppage time. Three days later, it won again at home on Mason Toye's goal in the 64th minute of a U.S. Open Cup semifinal. This time, the series goes back to Providence Park, where Portland is nearing the end of a 10-game homestand and plays 11 of its final 12 games there after stadium renovations sent it on the road for the season's first 12 games. Still, the Timbers find themselves just outside the playoff line. … United's Darwin Quintero's two goals in last Sunday's 3-1 victory over Real Salt Lake were his first since Aug. 14 and his first multi-goal game since April 19. He's tied with Christian Ramirez for the club career record with 21 goals in MLS play and holds the club record with 25 goals in all competitions since United joined league play.

Injuries: United D Wilfried Moimbe-Tahrat (left leg) is listed as questionable. He trained lightly Thursday in Blaine and afterward Heath said he'd be available on Sunday. Portland GK Jeff Attinella (shoulder), D Modou Jadama (foot) and Julio Cascante (thigh) are out, D Larrys Mabiala (thigh) and M Sebastian Blanco (lower leg) are questionable.