BASEBALL

MLB—Suspended Tampa Bay Rays minor league RHP Matthew Walker (FSL) for 50 games for testing positive for a performance-enhancing substance in violation of the minor league drug prevention and treatment program.

American League

CHICAGO WHITE SOX—Purchased the contract of LHP Clayton Richard from Charlotte (IL). Transferred LHP Andrew Sisco from the 15- to 60-day DL.

NEW YORK YANKEES—Placed C Jorge Posada on the 15-day DL. Activated OF Johnny Damon from the 15-day DL.

TEXAS RANGERS—Recalled pitcher Scott Feldman from Frisco (Texas). Optioned C Taylor Teagarden to Oklahoma (PCL).

National League

PITTSBURGH PIRATES—Recalled RHP John Van Benschoten from Indianapolis (IL). Optioned RHP Marino Salas to Indianapolis.

BASKETBALL

National Basketball Association

NBA—Named Bernie Fryer vice president and director of officials; Joe Borgia vice president, referee operations, and Ronnie Nunn director of development.

BOSTON CELTICS—Re-signed G Eddie House and G Tony Allen.

Women's National Basketball Association

SACRAMENTO MONARCHS—Re-signed F DeMya Walker.

FOOTBALL

National Football League

CLEVELAND BROWNS—Signed DE Christian Mohr as an international practice squad player. Waived DB Justin Sandy and DE Zach West.

DENVER BRONCOS—Signed C Kory Lichtensteiger. Waived RB Mike Bell and K Garrett Hartley.

KANSAS CITY CHIEFS—Signed RB Jamaal Charles and TE Brad Cottam to three-year contracts.

NEW ENGLAND PATRIOTS—Signed LB Shawn Crable and QB Kevin O'Connell.

NEW ORLEANS SAINTS—Acquired TE Jeremy Shockey from the New York Giants for second- and fifth-round 2009 draft picks.

OAKLAND RAIDERS—Released OT Jonathan Palmer.

TENNESSEE TITANS—Agreed to terms with DE William Hayes on a multiyear contract. Waived S Rocky Schwartz.