Ben Olsen hurt himself while scoring a goal and then aggravated the injury while scoring another one. Bobby Convey injured himself while apparently trying to prevent a goal. And Earnie Stewart hobbled off the field with a groin injury after attempting to set up a goal near the end of practice yesterday.

Three ailing midfielders, three headaches for United Coach Peter Nowak going into the match against the Los Angeles Galaxy at RFK Stadium.

Convey has been scratched, Olsen said he won't play, and Stewart will be tested before the 7:30 p.m. kickoff.

Speaking in general about the outbreak of injuries this year, Nowak said: "It's life. It's not easy. Even the little injuries, you have to keep the guys positive. You hope they'll be back very soon. . . . For the rest of the guys, it's a chance to jump into the team and play on a regular basis."

Olsen, who has started all but two games, said he strained his right quadriceps while scoring from long range in the dying moments of United's 6-2 victory over the MetroStars two weeks ago. He was well enough to play last week at Kansas City and in Wednesday's exhibition vs. Nottingham Forest, but during a meaningless penalty kick tiebreaker after the 1-1 tie with the English club, Olsen said he re-injured his leg on his winning shot in the fifth round of the shootout.

The injury, combined with other factors, could keep him off the field for several weeks. He probably will be questionable for next Wednesday's U.S. Open Cup game at minor league Richmond, and he's planning to miss next weekend's league match at Dallas in order to attend his mother's wedding in Pennsylvania. The wedding had been planned for MLS all-star weekend so Olsen could attend, but then the league pushed the All-Star Game back a week.

Convey, who is being pursued by England's Tottenham Hotspur, injured his thigh while playing for the U.S. national team in last Sunday's friendly with Poland in Chicago. Although Convey can't remember how he got hurt, United officials believe he made contact with the right post while trying to prevent Poland's goal in the second half.

Convey was in a great deal of pain that evening, and U.S. Coach Bruce Arena told United President Kevin Payne that a doctor should be contacted. The diagnosis was a hematoma, a local swelling filled with bloody fluid, which, if not treated immediately, could become serious.

"When I saw Bobby the other day, I noticed his pants [around his thigh] were bigger, and I thought he had something wrapped around it," United technical director Dave Kasper said. "But it was just from the swelling. The circumference of his leg grew by four inches."

Convey, who didn't play against Nottingham Forest, has been receiving treatments but has not participated in full workouts and appears unlikely to play in the Open Cup game next week.

Stewart, who has missed only one game this year, went down after crossing the ball from the right side during the informal portion of practice yesterday. He was escorted to the locker room and underwent treatments.

While replacements for Convey and Olsen seem clear-cut -- rookie Josh Gros would start on the left side again, and Jaime Moreno likely would move from forward to midfield -- Stewart's replacement on the right flank is up in the air. Ezra Hendrickson appears to be the leading candidate.

Besides the injuries, United has to be concerned about high-powered Los Angeles, which has the best record in MLS, is unbeaten in its last four games (3-0-1) and scored four goals in nine minutes the last time it visited RFK on May 19.

"We don't want to have that situation again," Nowak said. "I think everyone remembers that game."

MLS Notes: Midfielder Danny Szetela, one of the top young players in America, has turned down European offers to sign with MLS. Szetela, 17, will be assigned to a team via a weighted lottery next week. . . . Defender David Stokes declined an assignment to play for Richmond this weekend. "He felt he would be better off staying here," Kasper said.

Bobby Convey, left, here tangling with a Polish player, injured his thigh in last Sunday's friendly with Poland.