Union defender Sheanon Williams added to U.S. Olympic qualifying roster

Philadelphia Union defender Sheanon Williams has been added to the United States Under-23 men's national team for the Olympic qualifying tournament that starts Thursday in Nashville.

Williams was a last-minute callup after forward Josh Gatt was recalled by his Norwegian club team, Molde, after sustaining some injuries.

Look for either Chris Albright or 2012 SuperDraft pick Ray Gaddis to take over at right back for the Union while Williams is away.

This makes three Union players on the Olympic qualifying roster. In addition to Williams, Amobi Okugo and Freddy Adu were named to the intial squad. U.S. coach Caleb Porter has appointed Adu as the team's captain.

(Given how Adu has played under Peter Nowak, he will be particularly worth watching in a leadership role under Porter.)

Williams, Okugo an Adu will miss two Union games: this coming Saturday at Chicago and March 31 at home against Vancouver. The Union are off the weekend of April 7, then return to PPL Park on April 14 to face the Columbus Crew.

Here's the final U.S. squad for the Olympic qualifying tournament:

Saturday, March 24: United States vs. Canada, 7:00 p.m. (Universal Sports/mun2/CONCACAF.com)

Monday, March 26: United States vs. El Salvador, 9:00 p.m. (Universal Sports/mun2/CONCACAF.com)

Saturday, March 31: Semifinal vs. TBA, 9:00 p.m. (NBC Sports Network/mun2/CONCACAF.com)

Monday, April 2: Championship game vs. TBA, 8:00 p.m. (Universal Sports/mun2/CONCACAF.com)