Alternatively, doing everything we can to minimize Eloy's injuries makes sense. Not letting him play the OF does just that. We also avoid Eloy getting in the way of Robert, TA and Moncada defensively and hurting them, too.
Eloy is perhaps a marginally better OF than AV. But he's not good. Sox need him in the middle of the lineup hitting homers and driving in runs. Even moreso next season when one of Pito/AV are gone.
Sox need to to flank Robert with real OFs next season. Sign a RF (Nimmo makes most sense), let Pollock play LF until Colas arrives a month or so into the season, and then platoon the two thereafter. Pollock then becomes injury insurance for all of the OF, and Sheets is in AAA waiting for Eloy to get hurt. All of Eloy, AV and Sheets should only play the OF occasionally after this season.