If this had been a normal work week for D.C. United, with seven days between matches and a couple of days off, the club's growing list of injuries probably wouldn't have become such an issue.

But United is amid one of the busiest stretches of the MLS season, playing three games in eight days, including tonight's rare midweek encounter with the Los Angeles Galaxy at RFK Stadium. So instead of having time to evaluate ailing starters Ryan Nelsen, Ben Olsen and Bobby Convey and weigh his options, Coach Peter Nowak must test his roster depth right away.

"It's very important for us, especially the guys who didn't play much lately," he said. "We are pretty confident the guys are going to step up and they are going to fulfill their roles. We are ready for it. It's going to be a very interesting game for us."

Nelsen, an all-star defender, is sidelined with groin and shin injuries. Olsen, who has excelled in central midfield after years on the wing, is out with a strained quadriceps. And Convey, who runs the left flank, remains inactive with a hamstring injury. All are questionable for Saturday's game at Colorado, with a strong chance none will play.

That trio joins three attacking players sidelined since preseason: Eliseo Quintanilla, Santino Quaranta and Thiago Martins.

"From the beginning, everyone has been fighting for spots," said Olsen, who initially got hurt during a scrimmage against the University of Maryland a few weeks ago and aggravated it last weekend. "Everyone is ready. I don't see any reason for a letdown. . . . This is their shot. If they do great, I might not get my spot back."

But as bad as things are for United, they are worse for the Western Conference-leading Galaxy. Carlos Ruiz, MLS's leading scorer with six goals, severely sprained his ankle over the weekend and will miss at least two games. His frontline partner, Jovan Kirovski, didn't make the trip because of a sprained foot, and starters Danny Califf (knee), Tyrone Marshall (knee) and Peter Vagenas (groin) also stayed home, according to a team spokesman.

Nowak's lineup decisions, usually a mystery until kickoff, are a little clearer. Mike Petke, benched for a couple of weeks, is expected to step in for Nelsen in central defense. Rookie Josh Gros is likely to make his second straight start in place of Convey. And forward Jaime Moreno will probably step back into central midfield where Olsen usually plays, opening a frontline spot for Alecko Eskandarian or Freddy Adu alongside Ronald Cerritos.

Moreno has been United's top distributor in his withdrawn forward position and shouldn't have any trouble as a playmaker. "I like to play that position -- I get the ball more often," said Moreno, who in previous seasons would be called upon to play midfield when former teammate Marco Etcheverry wasn't available.

Meantime, Adu says he's enjoying himself more than he was the first month of the season and is becoming increasingly more comfortable.

"I'm having a lot more fun now," he said. "Something just clicked in me and I just forgot about everything else that was going on. Before, I was just thinking too much. Now I'm totally relaxed and playing my game."

Early in the year "I was too stiff. I was just trying to fit in way too much. I cared too much about what the other guys thought of me."

Adu seems set to come off the bench for the second straight game after a brief, yet influential, performance against Kansas City on Saturday.

"Of course, I want to start every time, but in a way [coming off the bench] helped me out because I was able to actually pay a lot more attention to the game, to see what some of the other forwards do, and then when I go in there, I try to add that to my game," he said. "My level of play will rise, I know it will."

United Notes: Quintanilla has recovered from a broken leg and is now trying to get into game shape. Quaranta and Martins, however, are still several weeks from returning. . . . The team is awaiting final approval of Ghanaian midfielder Nana Kuffour's visa application before activating him. . . . Nowak said Convey has been named to the U.S. national team roster for the June 2 friendly against Honduras in Foxboro, Mass., but his injury could deem him unavailable. . . . On Thursday Adu will travel to Bradenton, Fla., for his high school graduation. He'll rejoin the team Friday night in Denver. After Saturday's game against the Rapids, United will spend two days at the Colorado ranch of billionaire Phil Anschutz, who operates five MLS teams, including D.C.

United's Ben Olsen is out with a strained quadriceps. He joins fellow starters Ryan Nelsen (groin and shin injuries) and Bobby Convey (hamstring), who are also sidelined.