*Greetings from RFK Stadium. Gathering material for a print-online preview this weekend ahead of Sunday’s match between D.C. United and the Philadelphia Union at RFK Stadium.

No love lost between the clubs, who have engaged in several ill-tempered matches, most recently a preseason affair in which Dwayne De Rosario head-butted former teammate Danny Cruz.

A couple of sneak-preview quotes to share:

“I don’t like Philadelphia, to be honest with you,” goalkeeper Bill Hamid said of the team, not the city. “It’s always been like a New York and D.C. [rivalry]. Philly is a young group; I am a young guy. So I can relate to their hunger, their nastiness, their will to win. And they like bringing it.”

Ben Olsen, on United’s 1-4-1 start heading into the Philly match:

“The vibe is fairly good. It’s a balance of positivity and carrying a stick right now. I have tried  to manage that, but we have had good training sessions. The guys are talking and figuring out some things. … I am a fairly optimistic guy and we believe we can start this weekend moving up the table and get better.”

Olsen said De Rosario could play 90 after going 45 in his return from injury last weekend.

*El Salvador will play Honduras in an under-20 friendly at the University of Maryland’s Byrd Stadium on June 1 at 6 p.m., promoter Elias Polio said.

El Salvador is readying for the FIFA U-20 World Cup in Turkey, starting June 21.

Awaiting comment from Maryland athletic department…..

Byrd, home to Maryland’s football and lacrosse teams, had artificial turf installed last summer. The soccer teams play at nearby Ludwig Field, a multisport grass facility that can accommodate about 8,000 during the fall season. However, the temporary bleachers are not erected until the season approaches.

RFK Stadium was not available because of U.S. national team will play Germany on June 2.

Polio had been hoping to bring El Salvador’s full national team to RFK in late June for a game against a Latin opponent, but the date would have been too close to the Gold Cup and potentially undermine CONCACAF’s ticket-selling efforts for a tournament quarterfinal doubleheader four weeks later in Baltimore.

*After having him on loan this month, Sheffield Wednesday is optimistic about midfielder Stuart Holden rejoining the U.S. national team this summer. (The CONCACAF Gold Cup in July is more likely than the Belgium and Germany friendlies in late May and early June, and three subsequent World Cup qualifiers. U.S. assistant coach Andi Herzog recently attended a Sheffield match and met with club officials to assess Holden’s status after years of injuries.

*Fox Soccer has agreed to carry six National Women’s Soccer League matches — one per week starting July 8 — as well as the three playoff games in late August. The network and league have yet to determine which regular season matches will appear.

*New England Revolution goalkeeper Matt Reis, whose father-in-law was injured in the Boston Marathon bombings, appeared on CNN with Piers Morgan last night. He will appear on ABC’s “20/20” at 10 p.m. Friday, as well: