Gray (hamstring) threw a bullpen session Monday that went well, Ian Browne of MLB.com reports.
Gray's right hamstring has responded well to multiple throwing sessions over the past week, which likely sets the right-hander up to return from the 15-day injured list to start Wednesday's series finale in Detroit. Red Sox interim manager Chad Tracy plans to meet with Gray and chief baseball officer Craig Breslow before confirming Wednesday's scheduled starter. If the Red Sox elect to wait a little bit longer before activating Gray, Jake Bennett would likely be the top alternative to start Wednesday.