Colorado tries to avoid back-to-back home losses for the first time in four years Saturday night while Dallas looks to end its franchise-record 13-match winless stretch.
After Drew Moor's botched play led to the only goal in a 1-0 home loss to Vancouver on July 4, the Rapids (7-10-1) gave up two scores off corner kicks in last Saturday's 2-1 loss at Seattle.
"You've got to be big, you've got to be strong, but unfortunately that's what's killed us now," Moor told the league's official website.
Perhaps the 6-foot-2 Wahl can help with that after being acquired from Montreal on Friday for a 2014 international roster spot.
"Tyson is a natural left-footed defender with good skill and size," Rapids technical director Paul Bravo told the club's official website. "We're excited to be able to add such an experienced player without compromising our roster flexibility as we move into the second half of the season."
The Rapids, who last dropped two straight at home July 27 and Aug. 9, 2008, open a stretch of three matches in eight days with their second game against Dallas this season.
Jaime Castrillon and Martin Rivero scored in the second half to help Colorado snap a four-game road losing streak and defeat Dallas 2-0 on May 6. That was also FC Dallas' first home loss of 2012 after opening 3-0-2.
Dallas (3-9-7) makes its lone trip to Commerce City this season -- it lost 1-0 there Oct. 1 for its first 0-4 skid in MLS play since 2004 -- without a win since April 14 against the Impact.
However, coach Schellas Hyndman's club is coming off three consecutive draws, the latest scoreless with Western Conference-leading San Jose last Saturday.
Dallas goalkeeper Kevin Hartman has surrendered just one goal during that stretch.
"Maybe our luck is changing a little bit defensively, so now if we could get a few goals, it would allow us to enjoy the fruits of our labor," Hartman said.
The team hopes de Guzman can deliver some offensive punch after he was acquired from Toronto on Friday for midfielder Andrew Wiedeman.
"He also has a bit of toughness to him that will help us win 50-50 balls and control the central midfield," Hyndman told Dallas' official website of de Guzman.
Midfielder David Ferreira, the 2010 MLS MVP, is coming off his first start in 14 months due to a leg fracture, and midfielder Ricardo Villar returned last Saturday after missing 13 games due to a right foot injury. But Dallas leading scorer Blas Perez (five goals) could miss a fifth consecutive league match with a right foot sprain.
It's uncertain if Rapids first-year coach Oscar Pareja -- a former FC Dallas player, assistant coach and director of player development -- will start Omar Cummings, who is working his way back from a sprained ankle that sidelined him for more than a month.
Cummings scored his fourth of the season last Saturday as a second-half substitute.
FC Dallas, 0-3-2 in its last five games at Colorado, is trying to avoid its first five-game road losing streak since Aug. 21-Oct. 9, 2004.