Jose De Leon - Jose De Leon was part of the trade package, and the Rays are not necessarily ready to rush him back or in dire need, but De Leon is a talented arm who is ready to get his career started. The Rays have a deep rotation, so De Leon is not a lock to get right back into things. This is more to impact his potential start time in the MLB compared to the Rays trying to use him.
Jose Mujica - Jose Mujica is a 22-year-old right-hander who is expected to miss the entire 2019 season due to Tommy John surgery. This seems to be a step most pitchers are taking these days, and Mujica is getting out it out of the way. He is expected to make a full recovery, and will start to work his way back into future plans for Tampa next season.
Playing in Tampa Bay has led to a lot of short playing time, mainly because they are always a selling ballclub, but also because playing on that turf has led to some injuries. Going back to the 2004 season when they were still the Devil Rays, Seth McClung needed Tommy John surgery, whole Eduardo Perez went down with a torn Achilles within a month from each other. The Rays were already dealing with Rocco Baldelli coming off surgery on his left knee.
2008 was one of the most injury prone starts to a season we had ever seen for a club. Ben Zobrist, Scott Kazmir, Rocco Baldelli, Cliff Floyd, and Matt Garza all started the season on the DL either from Spring Training injuries, or recovering from offseason injuries. The Rays finished the season like they started, as Evan Longoria fractured his wrist. Carl Crawford needed to fix a tendon in his right finger, while Troy Percival had cartilage damage in his knee.
Evan Longoria had a couple of major injuries during his time in Tampa. He ended up tearing his hamstring back in the 2012 season, which led to another string of DL stints for him throughout the season. Both Desmond Jennings and Brandon Guyer fractured their fingers within a few games, sending them to the DL for the rest of the season. Matt Moore looked like a talented lefty at times, but the Tommy John surgery in 2014 started to hinder his ability.