Beltran was taken to the hospital for X-rays, leaving the Cardinals without one of their best players for most of the game.
He went back against the low wall, which measures nearly 5 1/2 feet, and caught Ortiz's drive with the bases loaded for the second out in the second inning. David Ross scored on the sacrifice fly to make it 5-0.
Beltran was holding his side and pressing his chest in the outfield before the inning ended. His was due up fourth in the top of the third, and Jon Jay was waiting in the on-deck circle when the half-inning ended. Jay went to centre field, and Shane Robinson shifted from centre to right.
One of the game's greatest playoff performers, Beltran is in the World Series for the first time in his 16-year career. The eight-time All-Star batted .296 with 24 homers and 84 RBIs in the regular season.
He entered hitting .337 with 16 homers and 37 RBIs in 45 career post-season games. He also had scored 44 runs, stolen 11 bases and compiled a .724 slugging percentage.
Beltran had 12 RBIs in the NL playoffs this year. He struck out in his only at-bat Wednesday night.