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Houston Dynamo's David Horst is eager to face his former team, but careful to "stay within" himself on Sunday

It is inevitably one of the first games a player looks for when the new season's fixture list is released—the clash with his former club.

David Horst did not have to wait long for a reunion with his old employers, as the Portland Timbers visit BBVA Compass Stadium on Sunday (2 p.m. CT, TICKETS) just four months after the defender swapped the Rose City for the Bayou City.

Horst spent three years with the Timbers and featured in the franchise's first-ever MLS game back in 2011. However, his 2013 campaign was cut short after just two appearances when he suffered a season-ending leg injury, coincidentally against the Dynamo. When Houston stalwart Bobby Boswell left for D.C. United last December, the Dynamo swooped to acquire the Pennsylvania native in exchange for a fourth-round pick in this year's MLS SuperDraft.

So far it has been a shrewd piece of business for Dominic Kinnear's side, especially since another ex-Timbers defender, Eric Brunner, is yet to play this year because of injury. Though Horst is looking forward to Sunday afternoon and knows it is no ordinary match, he is also aware that once the game kicks off he needs to forget the past and treat his erstwhile coworkers no differently from any other opponent.

"You always have something to prove to the team that you used to play for but I've got to stay within myself in the game. You can't get too crazy going into the game, I've got to keep a level head and just keep playing the way that I've been playing and that's all I can do," he told reporters on Friday at Houston Sports Park.

The 28-year-old has been a success story in the early weeks of his career in orange, providing composure, solid positioning and, at 6 feet 4 inches, a hefty physical presence at the heart of the defense. The only blemish came when he picked up a red card against FC Dallas for a late tackle, which earned him a one-match suspension.

But that was an aberration: it was Horst's first red card in an MLS career that began with Real Salt Lake in 2008. For a tough-tackling center back—indeed, for a player in any position—Horst's disciplinary record is remarkable. He has made 48 MLS appearances, logging 3809 minutes on the field, yet has only collected one yellow card, back in 2012.

The Dynamo will need him to be at his error-free best on Sunday. Horst's scouting report on Portland boils down to this: they are much more dangerous than their results this year suggest.

Former University of Akron head coach Caleb Porter arrived in Oregon ahead of the 2013 season and had an instant impact, leading the Timbers to first place in the Western Conference and being named MLS head coach of the year. The Timbers ousted arch-rivals Seattle Sounders in the Western Conference Semifinals but were beaten by Salt Lake in the penultimate round of the playoffs.

So far in 2014, however, the Timbers are yet to click into top gear. They entered the weekend as one of four winless teams in MLS—though they are hard to beat, having tied four of their seven matches.

"Portland's got a lot of attacking talent that's for sure between Darlington Nagbe, Diego Valeri and whoever plays up top for them. They're a very dangerous team. Their record may not prove it this year but all those guys proved it last year, they can score goals, they can create goals and they're going to keep the ball and make a lot of runs through," said Horst.

"There's going to be a lot of movement and we've got to track the runners and know where everybody is on the field. Everybody that's playing up top for them is dangerous so it's very important to know where each and every guy is at all times. It's early in the season yet and they've had some great goalkeeping performances against them. They're right there creating a lot of chances and they're still a very good team."

Kinnear agrees. "The one thing they're missing is a win. They have a lot of good players. They haven't had the results they've been looking for but I think they're a good team that can cause you problems in a number of ways," said the Dynamo head coach.

The home side are also eager to return to winning ways. The last Dynamo victory came on March 15 against the Montreal Impact. Kinnear said that part of his job this week has been to ensure confidence remains high.

"I think the guys have been through a couple of stretches last year where we had bad runs of results, it's never easy but I always say there are no easy games out there. You can't look ahead and go, we'll pick up three points there and there," he said.

"There's always tough obstacles in the way, the most important thing is to make sure your head's up and looking forward rather than kicking the ground and feeling sorry for yourself."