What happened: Arizona Diamondbacks starter Ryne Nelson is sidelined with both a flexor strain and a UCL strain and will undergo another MRI in four to six weeks. He hopes to return in September. Reliever AJ Puk has been shut down for another four weeks with a capsule strain and will also have a follow-up MRI in four weeks.

Why it matters: Losing Nelson from the rotation and Puk from the bullpen at the same time thins Arizona's pitching depth as the season wears on. A UCL strain in particular carries the risk of a longer recovery, and a September target would keep Nelson out for the bulk of the summer.

What to watch: Watch for the results of both follow-up MRIs, which will clarify whether either pitcher's timeline holds or slips further.