Thanks to his condition, he'd lose his head if it wasn't attached.
But instead, he found a severed head in a bag on Elementary Season 6 Episode 5 -- if only he could remember where he picked it up.
His post-concussion syndrome almost levels the playing field for Sherlock's fellow investigators.
It was an interesting twist to have viewers arrive after the train had left the station, so to speak.
Marcus and Joan were already interrogating suspects for a crime about which we haven't even been informed, so we had to play catch up already.
Then Sherlock added a wrinkle to the case of the week, losing his short-term memory of the previous six hours but acquiring a head in a bag. Why? He didn't know.
That forced Sherlock to suck it up and confess to Captain Gregson about his PCS. Gregson didn't approve of Sherlock's keeping him and the department in the dark. So now he was requiring Sherlock to receive the same medical clearances as any other person working for NYPD.
By not confiding in Gregson (and Marcus), Sherlock had blown the trust which had been building up with Gregson over the past six years. It will be intriguing to see how long that damage takes to be repaired.
Will Sherlock behave and jump through the hoops as Gregson has required? I suspect he'll do as little as he can get away with. His neurologist, Dr. Hanson, knows what to expect from Sherlock. The NYPD doctor, not so much. Sherlock will find a way to keep working.
So, the one thing Sherlock feared most about his condition has come to pass. He got sidelined, although mainly in name only, as Joan kept him briefed and she and Marcus turned up new developments and solicited the opinions he is always ready to offer.
This time off prompted Sherlock to run hard on a treadmill, as Joan indicated that exercise would have a positive effect on PCS. I think it's a cumulative benefit, not running fast will make the problem go away.
It certainly was a complicated case of the week, with suspects getting tossed out every five minutes.
It centered around tissue donation, with murders and arson used to wipe out any incriminating evidence. Of course, that was easy to do when the woman running the testing lab was the guilty party.
One murder is challenge enough. But when you have two murders, and both victims recently having skin grafts, things got complicated in a hurry, especially when Sherlock has the head of the donor body in his possession.
The nice thing about filming in New York is that it gives Elementary a different pool of actors from which to draw, in this case, Broadway. It's something that the Law & Order franchises had been doing for years.
In this episode, Tony winner Brian Stokes Mitchell played the ethically dubious director of a tissue bank. James Monroe Iglehart, of Aladdin and Hamilton fame, was featured on Elementary Season 6 Episode 3.
Anyway, Mitchell's character was guilty of nothing more than dodgy business practices, embalming a donor body to disguise any contaminants it might have carried.
Sherlock, Joan, and Marcus ran out of suspects reasonably quickly, until Joan hit upon the new tack of the donor body being valuable because of its resistance to avian flu.
In the end, it was the greedy researcher looking to make big bucks by supplying the necessary antibodies to produce a universal flu vaccine. It was a noble idea if she hadn't killed three people to get to that point.
Michael was back, and we got a better feel for his grand plan. As he explained to the support group in broad terms, apparently he killed that woman and buried her in the woods to keep Sherlock busy so that he wouldn't struggle so much with his sobriety.
Wouldn't more coffee klatsches have accomplished the same result, without all the, you know, killing?
That can't be all there is to Michael's vision, because that's just nuts.
Sherlock is starting to get a little suspicious of Michael, especially after he showed up at Sherlock's brownstone unannounced. Sherlock seemed a little put off by that behavior.
Then there's Joan's latest crusade. After looking into foster care on Elementary Season 6 Episode 4, the storyline never came up this episode. It seems it's going to be an occasional thing.
To view Sherlock's slow progress, watch Elementary online.
Did Michael reveal the extent of his plan? Will Sherlock get worse before he gets better? Can he and Gregson mend fences? Comment below.
Dale McGarrigle is a staff writer for TV Fanatic. Follow him on Twitter.