Santiago gave up five earned runs with five hits and four walks in 2.2 innings in Tuesday's loss at Seattle.
After going 4-1 with a 2.76 ERA in his first seven starts, Santiago has a 9.93 ERA in his last six starts. He's allowing 4.8 BB/9 and 4.4 HR/9 over that span. His continued slump could soon jeopardize his spot in the rotation.