Triple-A Sacramento placed Santos on its 7-day injured list May 26 due to a right adductor strain, MLB.com reports.
Santos maintains a spot on the Giants' 40-man roster but has spent most of the season at Sacramento, with whom he's turned in a 4.50 ERA and 1.50 WHIP over 14 innings across 12 appearances. The righty reliever is projected to return to action for Sacramento in late June or early July.