With the season starting to slip away, the Cincinnati Reds optioned rookie pitcher Rob Bell to triple-A Louisville, shaking up their rotation on the eve of an important stretch of games against the St. Louis Cardinals. The Reds planned to call up reliever Scott Winchester from Louisville today. . . . Cardinal third baseman Fernando Tatis, on the disabled list since April 29 because of a torn groin, will begin a four-day rehab stint with Memphis today and could but back on the major league roster by Friday. . . . Houston reliever Billy Wagner will fly to Los Angeles today to get a second opinion on his injured elbow. Wagner likely will miss the rest of the season and is facing surgery to repair a partial tear of the flexor tendon in his left elbow.