The 28-year-old already missed nearly four weeks of the season due to left knee troubles and has appeared in just 10 games with San Francisco on the year.
Robert burst on the scene in 2020 as an American League Rookie of the Year candidate and a Gold Glove winner, and he got off to a nice start this season before this illness cropped up.
When MLB added two more teams in 1997, the then-Devil Rays and Diamondbacks plucked players from each other franchise. Some worked out better than others.