Perhaps in today's sabremetrically charged environment, Trout will get consideration fro MVP. But when considering dominant offensive players, defense is almost always secondary, if non-existent. One of the knocks against considering a player like Ty Cobb as the "best all around player" of all time is the fact that his defense was suspect. Well, actually, it was just his throwing arm, I think. Cobb had incredible speed, and covered a lot of ground in the outfield. He positioned himself well, and understood opposing hitters well. He could fix his own poor fielding judgments with his speed. But he couldn't throw for squat.
Ted Williams was similar. But with him, the general sense was that he was a mediocre to poor outfielder who possessed a great throwing arm. In Ty Cobb's biography, there is an episode where he is interviewed as a fan at a game where the Red Sox where playing, and his comment was that while Williams was a great hitter, he wasn't much of a fielder. To his credit, Teddy Ballgame learned to play those fancy caroms in Fenway's left field well, and with the great arm he possessed, was able to throw out a lot of runners when the Red Sox were home.
My point? Nobody discusses defense when they talk about Cobb or Williams. Cabrera is not in the same league as those two, but he wasn't signed for his glove.