The Open champion shot rounds of 75 - 72 .
The Open champion missed the cut by one - a surprising result , given not only Johnson 's recent form ( four top - 6s in his last six starts ) , but also his history at Whistling Straits .
The Open champion shot rounds of 75 - 72 and missed the cut by one - a surprising result , given not only Johnson 's recent form ( four top - 6s in his last six starts ) , but also his history at Whistling Straits .