J.C. Ramirez - J.C. Ramirez is going to miss the first few months of the 2019 season recovering from Tommy John surgery. This was no surprise with the heavy slider usage and arm angle. Ramirez is a 30-year-old right-hander who found his way in the rotation later in the year. It will be interesting to see if he regains his spot in the rotation, as guys over 30 struggle to get their spot back unless they have been in that spot for a while.
Shohei Ohtani - Shohei Ohtani underwent Tommy John surgery after putting it off until the end of the season. Ohtani went on at DH with no issues, and eventually landed the Rookie of the Year award. Ohtani will likely not pitch in 2019, but his electric bat is going to be in the middle of the order again. The Angels will likely remain cautious with the 24-year-old, and keep him on some sort of schedule.
Zack Cozart - It was disappointing to see Zack Cozart go down in the middle of the season, especially after a strong 2017 campaign. Cozart had to have surgery on his left shoulder, but is expected to be back during Spring Training. It is not a given that Cozart makes this timeline, so it will be interesting to see if he is back. Cozart is also 33 years old, and on the older side for a ballplayer these things can go a little longer.
Back in 2002, Steve Green was coming up through the system, and ended up needing Tommy John. Green was never quite the same again, and eventually faded away in the minors. It was a disappointing season in 2004 for the Angels, who had loads of talent. Troy Glaus ended up missing most of the season with surgery on his shoulder. Tim Salmon also made numerous trips to the DL that season.
Garrett Anderson and Mike Napoli had injury prone seasons in 2007, which was another tough year for the Angels core players. Chone Figgins suffered a broken hand, and Juan Rivera broke his leg early in the season. Bartolo Colon also hit the DL a few times with elbow irritation. In 2011, Kendry Morales had surgery on his left ankle, which ended his time with the Angels, but he did make a full recovery.
We could section off a whole part for Garrett Richards, who is one of the more talented arms in baseball when healthy, but has struggled to stay healthy, with multiple surgeries in his career. The Angels have had horrible injury luck with pitchers as Tyler Skaggs had to undergo Tommy John surgery in 2014. Andrew Heaney also had to go to the DL, with a nerve injury in his elbow. Nick Tropeano followed him with UCL surgery.