With injured arms returning to the bullpen, Chicago must face a harsh reality: their veteran southpaw’s plummeting metrics and inflated ERA make him the primary roster casualty.
Reinforcements are on the way for the Chicago Cubs in the next few weeks.
Edward Cabrera, Hoby Milner, and Daniel Palencia should all return from their respective injuries very soon. Cabrera and Palencia should be back by mid-August, while Milner could be activated from the injured list within the next few days.
With their return on the horizon, the Cubs will eventually have to make room for those pitchers on the active roster. One easy move that the North Siders should make is designating left-hander Caleb Thielbar for assignment.
Thielbar was lights out for the Cubs last year, posting a 2.64 ERA and 56 strikeouts across 58 innings pitched. He was reliable out of the bullpen for the entire season and also threw three scoreless innings with four strikeouts in the postseason.
Those strong numbers led the Cubs to re-sign Thielbar to a one-year contract in the offseason. He showed no signs of slowing down last year and was going to be the team’s go-to pitcher against left-handed batters again. In 2025, opposing hitters batted just .161 with 27 strikeouts when facing the veteran reliever.
However, things have taken a turn for the worse in 2026. The 39-year-old has been one of the Cubs' worst relievers this season. He currently owns a 5.30 ERA and a 1.346 WHIP across 35 ⅔ innings pitched. His recent numbers on the mound also prove that his time in Chicago should be coming to an end.
Thielbar has an 8.18 ERA over his last 14 appearances dating back to July 8. He has given up runs in three of his last five bullpen appearances and has allowed six earned runs in 2 ⅔ innings this month. The southpaw almost blew a game earlier this week when he allowed four runs against the Dodgers and then recorded just one while giving up two runs against the Royals on Friday night.
As great as Thielbar was last year, he is not that same pitcher anymore. When Milner returns from the injured list, the corresponding move should be the veteran left-hander.
There isn’t much optimism that Thielbar can eventually turn things around on the mound. Most of his underlying metrics are down from 2025. His expected ERA (4.76), expected batting average against (.246), average exit velocity (89.2 mph), barrel rate (12.5%), and hard-hit rate (40.2%) all rank in the bottom half of the league.
It’s clear that the Cubs left-hander just doesn’t have it this year. He’s allowing a ton of hard contact through the air and isn’t doing his job in the bullpen. As the team gets healthier, Thielbar should be the first to go.
