The verb of the relative clause is "mastered" (the main verb of the sentence is "is"). "like" is a preposition not a verb. "like a predator on the prowl" is a parenthetical insertion.
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Anintita Is it possible to move "like a predator on the prowl" after the word "player" ?Grammatically yes, but it would not read so well. The intended idea that he is a "like a predator on the prowl" because he capitalises on weaknesses is less clearly expressed.