Cecil suffered what manager John Gibbons described as a significant tear in his left calf tagging Mike Napoli during a rundown in the eighth inning of Friday’s 6-4 loss to the Texas Rangers.
His loss is a significant one, as he was the club’s primary left-hander and top set-up man.
Tepera, who made his big-league debut this season, was 0-2 with a 3.27 ERA, allowing 23 hits in 33 innings over 32 games.
The 27-year-old is a reverse-split specialist, as right-handers posted a .746 OPS against him while left-handers were just .568.
Aaron Loup is the club’s only left-handed reliever on the playoff roster.