Relevant:
http://www.fanragsports.com/mlb/garrett-richards-key-angels-2017-season/
"Last season, the Angels struggled with both offensive production — despite Trout’s presence — and pitching injuries — losing Richards and Andrew Heaney to elbow ligament tears. While Heaney went on to have Tommy John surgery and will miss the entirety of the 2017 season, Richards has seen some success with an innovative stem-cell therapy program aimed at repairing or bolstering the ligament without the need for straight-up replacement. Per recent reports, Richards is throwing again, and will be ready for Spring Training and beyond.