Barco, who has logged 62 innings in his first full season since undergoing Tommy John surgery in 2022, was placed on the development list for High-A Greensboro on Tuesday.
Barco had surgery in May of 2022 and threw 18.1 innings in late 2023 after returning. He has been excellent thus far for the Grasshoppers, logging a 3.34 ERA, 1.10 WHIP and 77 strikeouts across 16 appearances, but Pittsburgh is keeping a close eye on his workload. It's unclear when Barco will return from his break on the development list.