Pending physicals and a few last-minute details, Texas has agreed to send first baseman Mark Teixeira and lefty reliever Ron Mahay to Atlanta for catcher/first baseman Jarrod Saltalamacchia, plus Minor Leaguers Neftali Perez and Elvis Andrus along with player to be named -- possibly pitching prospect Matt Harrison, currently injured. The move should considerably strengthen Atlanta and perhaps change the balance of power in the National League. Atlanta, which began the day in third place in the National League East Division, is 4 1/2 games behind first place New York and a game behind second place Philadelphia. Teixeira, who was batting .297 with 13 homers and 49 RBIs through Sunday, fills a void at first base, gives the club another left-handed power hitter and middle-of-the-order threat to complement the right-handed-hitting Andruw Jones and switch-hitting Chipper Jones. Teixeira's presence could also soften the impact if Andruw Jones departs via free agency after the season. Mahay strengthens a bullpen and gives Braves manager Bobby Cox another late-inning option against lefty hitters. The Rangers get shortstop phenom Andrus, currently in Class A, and Saltalamacchia, a switch-hitting catcher widely considered one of the better young hitters in the game. Harrison has had shoulder problems recently, and his health status may convince the Rangers to pick another Atlanta prospect.