Back in the carefree days of May, D.C. United played league matches on four consecutive weekends and spent the rest of the time healing wounds and working on team chemistry. June wasn't very stressful either with a rare Saturday off and one weekday game tucked into the schedule.

The pace picked up in July, but now August and September are presenting United with its most punishing stretch of the MLS season -- an eight-week spell in which the club could play as many as 14 games and have its depth severely tested amid its postseason push.

D.C. endured the first challenge, a 3-1 U.S. Open Cup victory over minor league Richmond on Wednesday in the first of eight games this month, but now it must turn its attention to league matches against the Chicago Fire tonight at Soldier Field and the New York/New Jersey MetroStars on Wednesday at RFK Stadium.

"We know we have a lot of games, but if we can keep our mentality going into this stretch, we know we can get some results," defender Bryan Namoff said yesterday. "Looking back to last year, this was the point of the season when we started to click, so hopefully we can make the same thing come to fruition."

If it weren't enough to play nine MLS games between today and Sept. 17, United also must prepare for an Open Cup quarterfinal against Dallas on Aug. 24; possibly the tournament semifinals in mid-September; and a pair of matches next month in the Copa Sudamericana, a major Latin American event, which will include a trip to Peru or Chile.

United is relatively healthy -- forward Alecko Eskandarian (concussion) and defender David Stokes (ankle) are the only regulars who remain out -- Ben Olsen and Santino Quaranta have returned from U.S. national team duty, and Namoff has recovered from hernia surgery. The club also plans to add two reinforcements after Aug. 15, when the international transfer window opens.

For the time being, however, Coach Peter Nowak seems pleased with his club's overall depth and its preparation for this demanding stretch.

"Every game we want to have players out there who are going to contribute to the team and keep the same level," he said. "If you see Chelsea and Arsenal, the number of games they are going to play, they need to have depth, but depth also means quality. I said to my guys: 'Whether you're young or a veteran, it doesn't matter. At some point in the season, you have to be ready for the challenge.' "

The primary challenge tonight will be on the back line as rookie Bobby Boswell, who has played every minute this season, serves a one-game suspension for an accumulation of yellow cards. United has no other natural center backs available, which means Brandon Prideaux likely will shift from the right to the middle and Namoff will start on the outside.

Prideaux has played in the center only a few times during his seven-year MLS career, but got a taste of the new role in the second half of the Richmond match.

"We'll see what Coach says, but I would presume I'll play there," he said. "It takes a little getting used to. We were a little rocky [Wednesday], but getting some time there helped out. . . .

"I'll have to read the game a little bit better. A lot of it is positioning, so it's a matter of understanding and staying focused. When you're outside wide, you're doing a lot of running, but centrally there's less running and more thinking."

Added Nowak, "It's not easy [without Boswell], but I think we'll be fine."

While Nowak's defensive options are limited, he will have more difficult decisions to make elsewhere: Quaranta or Freddy Adu alongside Jaime Moreno on the front line; Quaranta, Olsen or Dema Kovalenko on the right side of midfield; and Olsen, Kovalenko, Brian Carroll or Clyde Simms in the two defensive midfield slots.

United Notes: D.C. has lost its last five games in Chicago, including a 4-3 result in June, and is 2-8-2 all-time. . . . Nate Jaqua, the Fire's leading scorer with seven goals, is questionable after bruising his left ankle.

United defender Bobby Boswell, getting a hug from Dema Kovalenko, left, will miss tonight's game in Chicago for accumulating too many yellow cards.