No, it never remotely said any such thing.
There are many valid arguments to be made against defensive metrics (most of which have already been made in this thread), but grossly inaccurate statements like this are not one of them.
Our Friend Aaron Gleeman:
According to Ultimate Zone Rating as a duo Gomez in center field and Span in left field (or right field) has been 30 to 35 runs above average per 150 games. Meanwhile, as a duo, Span in center field and Young in left field has been 45 to 50 runs below average per 150 games.
The latter total is inflated by Span's unsustainably horrible numbers in limited action as a center fielder, but even if you ignore them to give him credit for being exactly average in center field — which at this point is far from a safe assumption — the Young-Span alignment is 40 to 50 runs worse than the Span-Gomez alignment. In other words, by benching Gomez for Young, the Twins are gaining 15 runs offensively and losing 40 to 50 runs defensively. All of which is why focusing on their batting averages is silly.
I remember this specific debate at BYTO...