Johnson (hamstring) threw Sunday and is still a top candidate to take the rotation spot of Eduardo Rodriguez (knee) and start Saturday, Rob Bradford of WEEI.com reports.
Concerns were raised after the pitching prospect left his scheduled start with the PawSox early due to a hamstring cramp, but it seems like the issue was fairly minor. Unless another setback occurs, most signals are pointing toward him being called up to start for the big-league club at home against the Tigers on Saturday.