Aaaaaactually...
I do get what you're saying, I'm honestly convinced Mike Lowell torpedoed the team's chances in 2009 by playing through IIRC a hip pointer that he could have gotten operated on, cleaned out and back in the game b y the playoffs, and at the time we had Jed Lowrie available as 3B depth.
He had the choice between playing 3 months with an increasingly debilitating injury, or getting the surgery he needed, cleaning out his hip, rehabbing for a month and taking the field in October. He made the wrong choice and was ineffective by September due to the limits imposed by his injury -- specifically the huge deficit in his already marginal range at third base. As a result his season bWAR was exactly zero, he was literally replacement level that year and trending downward by October It would have been better in the end simply to let Lowell go under the knife in July or August and get Jed Lowrie all the experience he needed to take over the position himself.
There's always pros and cons to the decision to rest or play a player. Personally though I see no reason right now to shut down Sale other than paranoid timidity, and that's no way to run a baseball team.