Ryan Nelsen says his abdomen feels fine. It's his lungs he's worried about.

Nelsen, D.C. United's all-star defender, is expected to return to the lineup tonight against the Chicago Fire at Soldier Field after sitting out six MLS matches and a U.S. Open Cup game. He hasn't played since mid-July, when persistent pain required him to undergo hernia surgery.

"I had forgotten how it was to run with no pain," said Nelsen, who has played in only 11 of 23 regular season games because of injuries and New Zealand national team commitments. "It was like three or four months of just non-stop pain, and now it feels so much better. The lungs feel a bit sore, though [from inactivity]. It's been a while since I've actually played. We'll see how it goes."

While the club is eager to welcome back its most important defender, it will have to make do without co-leading scorer Alecko Eskandarian for the second consecutive week. Eskandarian, who's tied with Jaime Moreno for the team lead in goals with seven, has made significant progress after spraining his left ankle 10 days ago but will have to sit out one more game.

"No question about it, I'll be back next week," he said after participating in the lighter portions of practice yesterday at the RFK Stadium training grounds. "I tried to get ready for this weekend, but it wouldn't be fair to the guys if I went out there and I can't cut or sprint."

The club suffered another setback this week when newly acquired midfielder Tim Lawson, who has been recovering from a strained quadriceps, suffered a second-degree ankle sprain and will be sidelined a couple weeks. He has yet to make an appearance after signing three weeks ago.

In addition, defender Ezra Hendrickson has rejoined the St. Vincent and Grenadines national team for a pair of World Cup qualifiers and is not available today. But with Nelsen's return, Hendrickson's absence probably won't have a major impact.

United Coach Peter Nowak, however, took a coy approach to Nelsen's availability. He did acknowledge that Nelsen would make the trip to Chicago, but "we played pretty good [on defense] the last couple of weeks and there's no reason to change anything. The way we're going to play is going to be the same."

Asked if he thought Nelsen would play, Nowak said, "I don't think so."

Later he added: "He's not 100 percent. We still don't know what our best options are. So many times a player comes back and the soccer part is not good. An injury set him back and we've got to see what we have to do the next couple of weeks to bring him along."

Nelsen did practice with the other probable starters yesterday and seemed to move well on the backline.

While United's lineup seems relatively firm, the Fire is scrambling to finalize its starters. Veteran stars Chris Armas and Ante Razov are out with injuries, Andy Williams and Damani Ralph have rejoined the Jamaican national team for World Cup qualifiers, reserve forward Dipsy Selolwane of Botswana is out of the country, and defender Evan Whitfield must serve a one-game suspension for accumulating yellow cards.

Chicago is only one point behind third-place United in the Eastern Conference following a 3-1 victory over Kansas City on Wednesday. United is enjoying a four-game unbeaten streak, the last three of those matches ending in ties. It is 1-6-5 on the road, with the only victory coming more than three months ago at New England.

The Fire's Rodrigo Faria tumbles as D.C. United's Ryan Nelsen clears the ball at RFK Stadium in April. Nelsen is returning from hernia surgery.