Scherzer is unavailable to pitch in Tuesday's game because he pitched for the Nationals on Saturday.
Gray's All-Star nod comes during a stellar rebound season for the 29-year-old. After experiencing a noticeable downturn with the New York Yankees in 2018, Gray joined the Reds during the offseason and has rediscovered his groove, posting a 3.59 ERA, 3.35 FIP, and 1.19 WHIP along with a career-best 10.3 K/9 rate across 17 starts.
This marks the second time that Gray has been named an All-Star. He last participated in the Midsummer Classic while pitching for the Oakland Athletics in 2015, the same season he finished third in AL Cy Young voting.
Scherzer, a seven-time All-Star, is in the midst of another Cy Young-caliber season and leads the league in multiple categories, including strikeouts (181). He's expected to travel to Cleveland for All-Star festivities despite being unable to play Tuesday, according to MASN's Mark Zuckerman.