The Chicago Cubs activated right-hander Hayden Wesneski from the 15-day injured list on Friday following his recovery from a right forearm strain.
In a corresponding move, the Cubs designated right-hander Shawn Armstrong for assignment.
Wesneski, 26, last pitched July 19 and is 3-6 with a 3.94 ERA, 21 walks and 58 strikeouts in 61⅔ innings over 25 games (seven starts).
He is 9-13 with a 3.96 ERA, 60 walks and 174 strikeouts in 184 innings over 65 games (22 starts) in parts of three seasons with the Cubs.
Armstrong, 34, was 0-1 for Chicago this season with a 4.91 ERA, 4 walks and 4 strikeouts in 7⅓ innings over eight games.
He also pitched this season for the Tampa Bay Rays (38 games, seven starts) and St. Louis Cardinals (11 relief appearances). His 2024 season totals are 3-3 with one save, a 4.86 ERA, 25 walks and 66 strikeouts in 66⅔ innings over 57 games (seven starts).
Armstrong has pitched parts of 10 seasons with seven teams. He has a career record 11-8 with eight saves, and a 4.15 ERA over 299 games (16 starts).
The Cubs (78-75) host the Washington Nationals on Friday and enter the day seven games out of the final National League wild-card berth.