Thompson played 29 games with the Pirates last season, including 22 starts, recording a 3-10 record with a 5.18 ERA. The 29-year-old owns a 4.44 ERA in 56 career games. He made his MLB debut with the Miami Marlins in 2021 after being drafted by the Chicago White Sox in 2014.
Pittsburgh designated Thompson for assignment on Jan. 5 after announcing the signing of starting pitcher Rich Hill.
Young, 25, split last season between Single-A Dunedin and Triple-A Buffalo, hitting .327 with six home runs and 22 RBI in 70 games. He was selected by the Jays in the 39th round of the 2016 MLB Draft.
Toronto designated pitcher Junior Fernandez for assignment to make room for Thompson.
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