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Red Bull New York will be looking to secure a second straight win on Sunday when it welcomes the lowly Portland Timbers to Red Bull Arena.

New York claimed a vital 2-0 home win over the Houston Dynamo last time out, positioning itself quite well for another postseason appearance.

The Red Bulls are well in reach for claiming a first-ever MLS Supporters' Shield, sitting just six points shy of the first-place San Jose Earthquakes.

Preparing for the final few months of the season, the Red Bulls have strengthened their squad with the additions of midfielder Tim Cahill and winger Lloyd Sam.

Cahill, formerly of English Premier League side Everton, played a starring role in New York's defeat of Houston, providing assists on both goals. Sam, who has joined the Red Bulls on a half-season deal with options at the end of it, will be unavailable for Sunday's tilt as he awaits his international visa.

Also missing for New York is Designated Player Rafa Marquez, who continues to be sidelined with a calf injury.

"It is a concern of course," head coach Hans Backe said. "As I said, when you pick up these calf injuries, it looks like, when we talk to the trainers, that he will be out two, three weeks. Then it takes time to come back if he stays fresh."

On the plus side, the Red Bulls will be able to welcome back right-back Brandon Barklage, albeit to the substitutes bench.

"He's available not as a starter," Backe said, "but definitely can be available for the bench [against Portland]."

The Timbers, who salvaged a point in a 2-2 draw with Toronto FC last time out thanks to a late goal from Darlington Nagbe, do not have much to play for through the last few months of the season.

Sitting at the bottom of the Western Conference on 21 points, Portland looks a strong bet to miss out on the playoffs yet again.

Portland has had to contend with a head coaching change this season as well as several key absences, something that interim boss Gavin Wilkinson believes has hindered his side's potential.

Wilkinson highlighted midfielder Franck Songo'o, who has not started more than four consecutive games, as someone who needs to be getting on the pitch regularly.

"He opened them up," Wilkinson said of the midfielder's performance against FC Dallas on August 5. "For Franck, he's a special player. We need to get Franck doing that week in and week out because you've seen what he can do, and now we have to get him on the score sheet a little bit more."