From the second the Seattle Sounders announced his signing, we knew Clint Dempsey's home debut was going to big. As it turns out, it looks like it has a good shot at being played in front of the biggest crowd in Sounders history.

On Tuesday, the club announced that its August 25 match against the Portland Timbers at CenturyLink Field was sold out, with some reports stating there have been more than 66,000 tickets sold. Later on Tuesday, the Sounders announced they have expanded capacity for the match, with another 400 upper-level bleacher seats and standing-room only tickets to be made available for the first time in club history.

Of course, a match against the hated Cascadia rivals was always going to be a big seller — their meeting last October drew 66,452 to the C-Link, the second-highest standalone attendance in MLS history — but this game has the opportunity to blow that one away thanks to the hype surrounding Dempsey's arrival. According to the club, more than 6,000 tickets have sold since the Dempsey announcement this past Saturday.

The Sounders are averaging more than 40,500 fans per match in 2013 with limited portions of the upper deck opened for MLS games. CenturyLink's maximum capacity is 67,000 for Seattle Seahawks games. In addition to last year's Portland match, the Sounders also drew 64,140 in a 2-1 win over San Jose in October of 2011, which was Kasey Keller's farewell match — that ranks as the fourth-highest attended MLS match.

The all-time attendance record for a standalone MLS match that was not part of a double-header is 69,255, set in MLS' inaugural season on April 13, 1996, when the LA Galaxy beat the MetroStars 2-1 at the Rose Bowl. (A double-header featuring a Chivas USA-New England MLS match and a Chivas Guadalajara-FC Barcelona friendly at the LA Memorial Coliseum in August of 2006 tops the charts with 92,650.)