D.C. United's injury woes took another devastating turn yesterday when doctors concluded that all-star defender Ryan Nelsen will require surgery for a hernia. Nelsen, United's top defender the last two years, will have surgery today in Milwaukee and sit out four to six weeks.

Nelsen's prolonged absence could have major implications for United (5-7-6), which yielded a season-worst five goals at Dallas last Saturday. Several D.C. defenders have had subpar seasons, but because of a thin roster, they have continued to earn significant playing time.

"Obviously, having Nellie out is a big loss, but we've got quality defenders and depth," United technical director Dave Kasper said.

In addition to Nelsen's injury, the team learned yesterday that reserve goalkeeper Nick Rimando needed arthroscopic knee surgery and forward Santino Quaranta will have a third procedure for his adductor/groin injury.

Rimando, who lost his starting job in May, had an operation yesterday at Virginia Hospital Center-Arlington and will be sidelined two to three weeks.

Quaranta, who has yet to play in a regular season game this year, is scheduled to undergo a two-part procedure this week and won't be ready to return for at least a month.

"We'll get through this," Kasper said. "It's a rough time, but we'll be fine."

Asked if the team was planning to sign replacements soon, he added, "We have some options right now and we hope to have some clarity within the next week."

United has been searching for help for several weeks, initially focused on scoring help after the team struggled to convert early-season opportunities. But with Nelsen out and others faltering, its attention might turn toward defensive reinforcements.

Kasper and team president Kevin Payne have declined to discuss specific players in whom they are interested, but it's believed they are looking at several foreign-based candidates, including 2002 U.S. World Cup player Tony Sanneh. The international transfer window for MLS teams to make acquisitions will open in about two weeks.

United's roster problems were so severe in Dallas, Coach Peter Nowak had to start five rookies and two second-year players, and had only three reserves available -- two of whom were acquired the previous day. (A team usually takes five substitutes on road trips.)

Nelsen has missed seven of 18 regular season games and three nonleague matches, primarily because of injuries. The club thought he had overcome his abdominal and groin ailments, but he continued to experience discomfort and had to make a second trip to a specialist in Milwaukee.

Rimando, who had major surgery on his left knee last fall, had an arthroscopic procedure on his right knee yesterday after undergoing an MRI exam on Monday. "It's been bothering him for quite a while," United spokesman Doug Hicks said.

"With the all-star break, we felt it was a good time to take care of it."

The club, which is off until Aug. 7, plans to acquire a goalie next week to back up starter Troy Perkins.

Quaranta, who has been beset with various injuries since his impressive rookie season in 2001 at age 16, made his debut this year during an exhibition against English club Nottingham Forest on July 14. But the adductor problems reemerged, and both a plastic surgeon and a nerve specialist will perform procedures on him.

MLS Notes: The number of All-Star Game scratches increased to seven yesterday as Nelsen, United midfielder Ben Olsen (quadriceps), Colorado defender Pablo Mastroeni (quadriceps), New England midfielder Clint Dempsey (jaw) and Kansas City forward Josh Wolff (knee) were ruled out.

Midfielders Bobby Convey and DaMarcus Beasley, who were sold to European clubs last week, are also unavailable for Saturday's exhibition at RFK Stadium.

Four Eastern Conference replacements have been named: United midfielder Dema Kovalenko, Columbus defender Robin Fraser and New England midfielders Steve Ralston and Shalrie Joseph.