A day after being claimed off waivers, Shawn Armstrong is joining the Cubs bullpen.

The team activated the veteran righty reliever prior to Saturday’s game against the Nationals and optioned righty Daniel Palencia to Triple-A Iowa.

Armstrong, 33, was designated for assignment on Tuesday by the St. Louis Cardinals. He had a 2.84 ERA in 11 relief appearances with St. Louis, including a scoreless streak of 7 games before he was let go by St. Louis.

[WATCH: Craig Counsell’s media availability prior to Saturday’s game against Nationals]

The Cardinals acquired the veteran at the trade deadline from Tampa Bay for outfielder Dylan Carlson. He has a lifetime 4.17 ERA in 291 games with six different organizations.

His addition provides a jolt to the Cubs bullpen that has been tested this week. Friday night against the Nationals, the Cubs saw a 4-run lead dwindle to 1 in the 9th inning, as manager Craig Counsell had to use 3 relievers to pick up the final 3 outs of the game.

Part of that was due to injuries — Jorge López, one of Counsell’s high-leverage arms, suffered a groin injury Monday and threw a bullpen session pregame Friday to determine health. Ethan Roberts exited Wednesday’s thrilling comeback against Pittsburgh with ankle soreness and threw a bullpen Friday, too.

Porter Hodge, another leverage arm, had pitched on back-to-back days on Tuesday and Wednesday and Counsell was avoiding using him on Friday night.

Armstrong’s addition should provide some needed veteran experience and a fresh arm.

Palencia has a 7.11 ERA in 9 relief appearances for the Cubs. He’s been an intriguing bullpen arm all season — he touches triple digits with his fastball but has struggled to harness that power, amassing a 19% walk rate in the big leagues.