The 27-year-old exited Monday's game against the Chicago White Sox at Guaranteed Rate Field with a hamstring injury and will clearly need some time for recovery. He was batting .313 on the season with 12 home runs in 73 games.
The Yankees called up middle infielder Tyler Wade to replace him on the roster.
Castro is in the midst of one of his best seasons and could set a career high in batting average if he keeps his current pace. He could also top last year's high of 21 home runs if he stays on the field.
Unfortunately, injuries have been a bit of an issue over the past week. He missed Sunday's game because of a wrist injury then left early Monday with the hamstring injury after trying to beat out a grounder.
It appears the Yankees will now turn to Wade, a 22-year-old left-hander who is hitting .313 with five home runs in Triple-A. Although he has primarily played shortstop this season, he has also spent time at second base, third base and each outfield spot.
Ronald Torreyes and Rob Refsnyder can also fill in at the position if needed for as long as Castro remains unavailable.