On his 107th pitch, Mariners starter James Paxton let go of the ball and grimaced. That caught the attention of catcher Mike Zunino, who called for the trainers, who looked at Paxton, who pointed to his chest before leaving the game. That, without any question, is the most important story to emerge from Thursday’s game against the Angels. The Mariners announced that Paxton had left with a left pectoral strain. More updates will be provided after the game. Paxton is not only the Mariners’ ace, a pitcher receiving consideration as a Cy Young candidate. He is the one reliable starter in the Mariners’ decimated rotation. Against Kole Calhoun in the seventh inning, Paxton rolled his shoulders and grimaced after throwing his 107th pitch on the night. It was enough to catch the eye of Zunino, who motioned for trainers.