Jimmy Nelson - Milwaukee was happy to rely on their bullpen over their starting rotation last season as it was one of the best in the league, and Milwaukee’s rotation was injured and subpar last season. Jimmy Nelson missed the 2018 season, and before has shown spurts of being a viable option in the rotation. He is due back for the 2019 season, and should resume his top spot in the rotation. This will give Milwaukee an added bump, but they will likely remain cautious.
Brent Suter - Brent Suter was having a decent season but underwent Tommy John surgery in August. Suter is likely going to miss the entire 2019 season rehabbing, as 2020 is a more estimated time frame. Suter is a backend starter, but Milwaukee is going to look for help wherever they can get it.
Back in the early 2000’s, Mark Leiter was rounding out a successful career, but he dealt with bicep injuries in the 2001 season that made him miss just about all of it. Valerio De Los Santos battled arm issues all his career, and never panned out because of his durability. This was a loss for the Brewers as they expected him to be a big part of their future. It was the same thing for Ben Sheets a few years later, who battled shoulder issues and never reached what the Brewers were expecting out of him.
In 2008, Yovani Gallardo tore his ACL, missing most of that season. Eric Gagne had come over from Los Angeles, but was never quite the same closer. He ended up with rotator cuff injuries for most of his time in Milwaukee. Chris Capuano had a torn ligament in 2008, causing him to rehab into the 2009 season. The Brewers put together some strong team of veterans in the 2012-2013 seasons, but Corey Hart needing surgery on his knee, and a few other names like Mat Gamel also missed some time.
Over the later years, Milwaukee has had some good fortune. Jimmy Nelson has been the bigger name to go under the knife for shoulder surgery. We have also seen an aging Ryan Braun start to hit the DL more with nagging injuries.