The Seattle Mariners are facing a challenging end to the season with several injury updates impacting their pitching staff. Reliever Gregory Santos is showing signs of recovery, having made three rehab appearances and may soon be activated, though he has only appeared six times for the Mariners this season due to prior injuries. Meanwhile, the team announced starter Luis Castillo will be on the 15-day injured list and reliever Yimi Garcia is out for the season. Additionally, promising prospect Teddy McGraw is sidelined with an elbow flexor issue that could require surgery, raising concerns given his recent Tommy John history. In Boston, Tanner Houck is set to return to the mound after shoulder fatigue delayed his previous start, as the Red Sox aim to keep playoff hopes alive despite trailing in the wild card race. Houck, who has been the team's best starter with a 3.24 ERA, will pitch three more times this season as the Red Sox face tough competition for a playoff spot.