The Red Sox’s nightmare season may have taken another unfortunate turn Sunday.  Starter Ranger Suarez exited in the fourth inning of the final game of their weekend series with the Astros with right hamstring tightness.  Suarez had thrown 70 pitches through four scoreless innings and allowed three hits before exiting the game.  The NESN broadcast appeared to catch the moment that he alerted the Boston coaching staff about the issue. Ranger Suarez throws a pitch during his May 3 start for the Red Sox. Getty Images Video showed Suarez walking off the mound into the dugout and telling pitching coach Andrew Bailey something as he went down the steps.  Suarez has had hamstring issues in the past, which included a 15-day stint on the injured list in August 2023 while he was with the Phillies and a seven-day IL stint when he was in the minors in 2018.  The left-hander entered Sunday off a start last week when he allowed one hit through eight scoreless innings in a win over the Blue Jays.…