The last year Maggs was healthy, he failed to hit 30 homeruns AND failed to get 100 RBIs.
I'm not sure Maggs' upside is that much higher than Matsui. It's not worth the risk imo.
"And so he spoke, and so he spoke, that lord of Castamere. But now the rains weep o'er his hall, with no one there to hear." - The Rains of Castamere