Martin wasn't available to pitch Sunday against the Athletics due to back stiffness, Jeff Wilson of the Fort Worth Star-Telegram reports.
The Rangers held a one-run lead heading into the ninth inning of Sunday's series finale, but with Martin unable to go, Jose Leclerc got the call. He would blow the save and take the loss. Texas has a scheduled off day Monday, so Martin will get an extra day to rest before the Rangers determine his status for Tuesday's clash.