By the middle of the week, D.C. United was certain forward Alecko Eskandarian had fully recovered from a concussion and would be able play in tonight's match at Columbus. He had rejoined practice for the first time since being kneed in the head by New England goalkeeper Matt Reis two weeks ago and, although he skipped Wednesday's game at Chicago for precautionary reasons, he appeared ready to try ending his season-long scoreless streak against the Crew.

However, Eskandarian began experiencing headaches late in the week and, as United packed its bags for the short flight to Ohio yesterday, he was scheduled to see a neurologist.

"It's still a dangerous situation and we just need to be very, very careful," Coach Peter Nowak said. "We monitor the situation every single day and see how he feels. We just hope in the next couple days he's going to be better."

Eskandarian, a high-energy striker from the University of Virginia who doesn't shy from hazardous situations in the penalty area, has suffered three concussions since entering MLS in 2003. This season he has also been hampered by knee and quadriceps injuries.

When healthy, Eskandarian struggled to regain his scoring form. Nowak turned to Santino Quaranta recently, but then he was called in to U.S. national team training camp.

Jamil Walker is an option, but he hasn't taken advantage of his scoring opportunities, most recently Wednesday when he entered late in the game and missed on a partial breakaway during the 4-3 loss.

If not for the concussion, Eskandarian probably would've returned to the starting lineup this week. Instead, second-year player Nana Kuffour, usually an attacking midfielder, joined Jaime Moreno up front for the Chicago match and might start again tonight. Kuffour, 20, scored his first career goal in league play against the Fire and began to build some chemistry with the veteran Moreno.

"They understand each other very well," Nowak said. Kuffour is "pretty good on the ball and he can keep possession. He's flowing all around, and that's why he's so dangerous."

Kuffour, a native of Ghana, started one game last year, but only because United was badly short-handed. He has performed well in reserve games this season and is beginning to understand Nowak's system.

Before Wednesday's game, "Jaime told me I'm skillful, I'm strong, I'm fast and I should be confident when I play the game and I shouldn't be nervous," Kuffour said. "Any time I got the ball, he told me, 'Nana, go, go! Do your thing.' "

While United's attack has found its rhythm, scoring nine goals in the last three games following three straight shutouts, the defense has regressed. Brandon Prideaux might lose his starting spot to David Stokes after making some mistakes Wednesday.

"The effort was there, but sometimes we were one or two steps slower," Nowak said. "We have to organize ourselves better. It's not only for our backs. The whole problem starts up front where we're too careless and we didn't pressure in the midfield."

Options are limited because Bryan Namoff is sidelined for an extended period with injuries, Kenny Arena hurt his ankle and rookie Tim Merritt isn't ready for regular action.

Nowak and other team officials scouted players in Argentina last week, but a signing would take weeks to complete.

United Notes: Midfielder Dema Kovalenko missed practice to attend a funeral in Rochester, N.Y., but is expected to play tonight. . . .

Namoff will fly to Germany on Tuesday to see a specialist about his groin/abdominal injury. . . .

United signed several players, including former MLS forwards Eric Quill and Felix Brillant, to weekend contracts in order to be able to field a full squad for Sunday's reserve game against the Crew. . . .

United will face the minor league Richmond Kickers or the amateur Ocean City (N.J.) Barons in the U.S. Open Cup's fourth round on Aug. 3, the U.S. Soccer Federation announced.