Muscle does not make a hitter. Robles, like MAT, has trouble getting the bat on the ball.
It's interesting. Some of the swing data says it was not so much swinging at more bad pitches or taking too many called strikes. Swing % stayed the same as prior year. It was more swinging and missing, especially balls in the strike zone.
https://www.fangraphs.com/players/victor-robles/18363/stats?position=OF