The calendar of Sounders FC's offseason is filling up fast while the team works to keep some key players.

Sounders FC’s season ended only 11 days ago. But much is already in the works for the rest of this year and early 2010.

Monday, the day after the MLS Cup at Qwest Field, the team has a half-day window to make a trade. By later that day, it must submit its protected list of 11 players and designated player Freddie Ljungberg to the league office, the 12 players the Sounders want to keep from being selected by the new Philadelphia Union in the MLS expansion draft Wednesday.

“We’re close,” Seattle general manager Adrian Hanauer said. “There are one or two at the end that are a little tougher for us, but for the most part, we know who we’re going to protect.”

But Hanauer added that the team won’t rule out a trade Monday.

From Dec. 18-20, Sounders FC is hosting an invitational tryout in Las Vegas. The three days of games are for college players and United Soccer Leagues players out of contract that are not invited to the pre-college draft combine in January. Foreign players could also be among the 70 or so invited.

The predraft combine is Jan. 9-12, with the college draft Jan. 13 in Philadelphia. Sounders FC opens training camp for next season during the third or fourth week of January — based on when the collective-bargaining agreement between the players union and owners is reached — and a trip to Spain for a preseason tournament is also on the docket for early next year.

The club is expected to travel to California or Arizona for preseason fitness, working out in better weather.

As for the players, only one Sounder from 2009 had his contract expire, defender Tyson Wahl. The rest are either under contract for at least next season, or the club has a contract option on others.

“We’re talking to Tyson and his agent,” Hanauer said. “We’re hopeful that Tyson will want to be back here and we can put a deal together that makes sense to both sides.”

Defender Jhon Kennedy Hurtado and forward Fredy Montero are on loan to MLS, which signs players on behalf of Sounders FC. But the club has the option to buy controlling interest in their contracts.

“We’re very happy with both Hurtado and Montero and we’re working toward keeping those players for another season and possibly seasons beyond that,” Hanauer said.

José Miguel Romero: 206-464-2409 or jromero@seattletimes.com