"If there's a chance today, we'll use him," Montoyo said, according to Hazel Mae of Sportsnet.
Pearson had been sidelined since Aug. 18 with an elbow injury. Prior to that, he posted a 6.61 ERA, 1.53 WHIP, and 14 strikeouts across 16 1/3 innings.
The 24-year-old has not pitched in relief during his professional career.
Toronto designated Wilmer Font for assignment in a corresponding move. The 30-year-old posted a 9.92 ERA and 4.77 FIP over 16 1/3 innings while making 21 appearances.