The Yankees selected Lombard's contract from Triple-A Scranton/Wilkes-Barre on Tuesday.
Lombard is starting at shortstop and batting eighth in his major-league debut Tuesday versus the Cardinals. The 20-year-old slashed .268/.405/.440 with six home runs and 10 stolen bases across 262 plate appearances for Scranton/Wilkes-Barre since he was promoted from Double-A Somerset. Lombard is in line to serve as the Yankees' primary shortstop down the stretch.