Second baseman Ian Kinsler has been scratched from the Texas Rangers' lineup and replaced by heralded prospect Jurickson Profar.
Kinsler developed stiffness in his lower back Sunday.
When he takes the field at Cleveland, the 19-year-old Profar will become the youngest active player, the first born in 1993 to play in the majors.
Profar hit .281 with 14 homers and 62 RBIs at Double-A Frisco. He homered in the Futures Game in July in Kansas City during All-Star week.
Profar is poised to become the third-youngest player in Rangers history behind pitchers David Clyde and Wilson Alvarez.
Kinsler, hitting .266 with 16 homers and 66 RBIs, missed four of Texas' first 132 games and is available.