Bad to worse: Portland Timbers defender Mikael Silvestre out with torn ACL

The injury concerns for the Portland Timbers' defense just got much worse, as the club announced Friday that defender Mikaël Silvestre suffered a torn ACL on his left knee on Thursday in the Timbers' 0-0 draw against the New England Revolution.

The injury happened in the 55th minute, when Silvestre stretched to keep a ball in play in the Revs' box and landed awkwardly on his right ankle and then his left knee. He was stretchered off the field and replaced in the game.

Silvestre is expected to be out six to nine months, the club said in a statement. He will undergo surgery when his knee is stablized.

The blow to Silvestre is the latest for the Timbers this season. Fellow starting center back David Horst broke his leg last month and underwent surgery, with an estimated six months out of the lineup. The club also announced Friday that it signed Gambian-Norwegian defender Pa Modou Kah to shore up the defensive corps.

In his first season with the club, Silvestre, 35, started eight of the Timbers' first nine matches of the season, logging 688 minutes and helping the backline record three shutouts.