Stephen Keel has spent the past few offseasons flipping houses with his father in the Colorado mountains — buying foreclosed properties and doing the necessary carpentry work and electrical and plumbing upgrades before reselling them.

His other job? The one with the Red Bulls? That might be Keel's best rebuilding job of the year, because since he's been a starter the Red Bulls defense is suddenly watertight and no longer leaking goals.

“It’s been a wild one,” Keel said Tuesday about his season-long journey, which continues tonight with a wild-card playoff game against FC Dallas in Frisco, Texas. “Looking back eight months, to come in and be where I am right now is crazy. For me, it’s about not getting too ahead of myself. I’m just coming in here and trying to get better every single day.”

And he has.

When it became clear that the central defensive tandem of Tim Ream and Rafa Marquez was not working, Red Bulls coach Hans Backe pushed Marquez and his $4.6 million salary to the midfield and inserted the unknown Keel, who will earn $42,000 this season, half the league’s median salary.

“It’s been good,” Keel said of his partnership with Ream. “We’ve kept three or four clean sheets. The communication has been solid from the beginning.”

Ream, the clear leader on the defense last season, never gelled with Marquez. Both are players who like to direct the attack from the back and Ream, being a second-year player, deferred too much to Marquez, and his play suffered.

“It’s tough playing next to a guy who’s that good,” Ream said. “With the way he plays, it’s one of those things where I was putting a lot of pressure on myself to be that good. I’m not. I’m not him. He’s proven it at every level. With Stephen, the onus is on me to play the ball out of the back. I don’t have to defer to him. I can make my own decisions.”

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With Keel, both players know their roles.

“We’ve both found a comfort level with each other,” Ream said. “We know what each other is going to bring to the table and we complement each other pretty well. We know that we’ll fight for each other. He’s going to cover me and I’ll be there for him.

“With Keel, what you see is what you get. He’s a hard-nosed defender who will go into tackles and try and win everything he can.”

Keel, a Littleton, Colo., native, played a combined 10 games with the Rapids in 2007-08, and had been playing with the minor-league Portland Timbers before signing with the Red Bulls March 9, 10 days before the season began.

With Marquez and Ream missing time with the Gold Cup and other international call-ups, Keel was given playing time and impressed with his solid play.

“My objective and my goal is defense first,” said Keel, who played 16 games (13 starts) this year. “First and foremost my goal is to defend. Anything I can add going forward is a bonus.”

The switch to Keel came Sept. 17, coincidentally, against FC Dallas in Texas, a game the Red Bulls won, 1-0. Keel didn’t play the next game, a 3-1 loss to Real Salt Lake, but played the final five games. The Red Bulls won three by shutout and only allowed three goals.

The Red Bulls have an option on Keel’s contract for next season and it should be the easiest decision the club will make in the offseason. While Keel says you can make a decent living in the housing market, even in this troubled economy, soccer is his first priority.

“That’s not even up for debate,” he said. “My main goal is soccer, 100 percent. Even when I’m doing the housing stuff I make sure I get my workouts in, but I’m not ready for that (full-time) yet. My dad has other guys to help out, but we don’t turn them over quite as quick when I’m not there.”

NOTE: Forward Luke Rodgers did not travel with the team due to an inflamed knee, which Backe says might be infected. His status for the next round of the playoffs, should the Red Bulls advance, is unknown.

Frank Giase: fgiase@starledger.com