This has some shades of Edgar Santana to it, who was an effective reliever for the Pirates in 2018, underwent Tommy John surgery that off-season, and missed all of 2019 and 2020, both because he was recovering and because of a PED suspension, before being traded to the Braves. Although Santana wasn't bad in 2021, he had fallen off hard from his 2018 peak.
The only other pitcher I could see potentially making a worthwhile impact in 2024 is Yerry De Los Santos. The right-hander had shown some talent in 2022 and 2023 and was once considered one of the Pirates' better relief pitching prospects. He's also only 26. De Los Santos is in camp with the New York Yankees and could find himself at the back of the Yankees' pen to start the year. But it's not a guarantee that he makes the roster, nor is it a guarantee he can stay healthy long enough to make an impact.
Overall, the Pirates didn't lose much in terms of talent, but they did lose some guys who could have been decent depth.
The one that stung the most to me was Perdomo. Even though he had undergone TJ surgery, I would have liked to see what he could do in the future. I am happy that Andujar will get a shot, as he wouldn't have had that opportunity with the Pirates. Even if it is a long shot for him to regain any semblance of his 2018 season or September 2023 over a full season, it is nice seeing a guy who has had constant injuries battle back and get an opportunity to make a comeback. In the meantime, the team did bring in a new lefty on a minor league deal to help fill some of the lost depth.