My guess is he mostly pitched in clean innings and not in high leverage situations. I do not trust him with men on base in a close game.
Since June 8:
High leverage: 2 IP, 4.50 ERA, .250/.286/.429 allowed
Medium leverage: 8.2 IP, 3.12 ERA, .172/.273/.345 allowed
Low leverage: 23.2 IP, 2.66 ERA, .172/.226/.221 allowed
Last 11 games:
High leverage: 0.1 IP, 0 ERA, .500/.500/1.000 allowed
Medium leverage: 3 IP, 0 ERA, .000/.182/.000 allowed
Low leverage: 7.2 IP, 0 ERA, .080/.080/.080 allowed