Clues generally come in two sizes: small and those that are dead giveaways, so large they can be seen from outer space.

During World War II, Joseph Stalin’s spymasters established a front in Brussels they named the Foreign Excellent Trench Coat Co. After all, what self-respecting spy could operate without a trench coat?

Yet, for some reason, perhaps the inability to provide trench coats, the Foreign Excellent Trench Coat factory was a bust.

And that, naturally, brings us to Gotham’s professional teams and the inability of its managements to see what’s coming, then wait too long to seek a remedy.

In sustaining the counterproductive presence of Gary Sanchez — and paying him more for his presence — it certainly seems the Yankees were the last to know that he was more doorstop than backstop. He was MLB’s highest salaried listless retriever of passed balls.

Reader Joe Nugent: “Poor [ex-Yankees pitcher] Sonny Gray, traded to the Twins the same day they get Sanchez to catch him again.”

That Sanchez conspicuously resisted all attempts, including private tutoring, to become even a minimally efficient catcher who ran the bases, with even a minimal degree of enthusiasm and situational awareness, and batted with the goal to hit the ball rather than strike out, only seemed to escape Aaron Boone, Brian Cashman and YES’ broadcasting teams.

But such is life in the big city.

Robinson Cano is back to play, somewhat, for the Mets after his second PED suspension. As a Yankee it was clear that Cano was a minimalist, that the fundamental, winning baseball act of running to first was beneath him.

As an aging — who isn’t? — Met, his disinclination to reach first base in even a moderately quick fashion was excused, explained and rationalized by the pandering as a veteran “trying to save his legs.”

Save them for what? He’s a professional ballplayer!

Also commonly heard in Cano’s defense was that, “He’s a great guy for the younger players in the clubhouse.”

But the game isn’t played in the clubhouse. What could he teach or preach in the clubhouse that he couldn’t on the field? To hustle, to guard against being only partway to first after the ball was dropped or a bad throw? Maybe he taught them how to cut off the crust on their cheese sandwiches.

When the Mets did what struck many as ridiculous — naming player agent Brodie Van Wagenen their GM — the move didn’t meet with the ridicule it deserved. Then it became what it had to become: a bad joke.

By the time then-exec Sandy Alderson brought Yoenis Cespedes to the Mets, Cespedes was a well-known laggard who’d jogged his way out of Oakland, Detroit and Boston, good riddance. After a hot run here, he was no different, though his golf game improved as he played when he was rehabbing on the injured list.

Still, the Mets re-signed him for a mere $110 million. Shortly later, he was gone with the wind, as was his former agent, Van Wagenen, having previously been replaced by Alderson.

The Nets did no research on James Harden? On why Houston had had it with him, on how he was, and remains, an early-morning party partaker with minimal dedication to his profession and professionalism? Enter Ben Simmons, who’s day-to-day, month-to-month.

The Jets didn’t know that running back Le’Veon Bell had become expendable in Pittsburgh because he was a full-time pain in the arse? He stayed in character to become quickly expendable as an underachieving Jets’ full-time pain in the can.

There was slim evidence that Carmelo Anthony could or would do what the best players do: make those around him better.

To the contrary, Anthony was a stat sheet superstar as the Knicks competed one-on-five on offense. Oddly, he was a good inside passer — but only as a last, double-teamed resort.

He hurt the Knicks more than he helped. It was hard to miss. Yet the Knicks re-signed him for an additional fortune.

Maybe at first the Giants felt that their 2017 first-round pick, tight end Evan Engram, would be special. But by his second then third year it had become evident that he’d remain what he’d become: a poor blocker with volleyball hands.

This week — likely to the relief of Giants fans, similar to the relief of Yankees fans with Sanchez’s departure — Engram signed with Jacksonville, which will pay him a guaranteed, flabbergasting $9 million for this season.

But the folks who run teams in Florida can’t be expected to be sharper than those who run teams in New York City. Besides, let some other town be the last to know. Need a trench coat?

TV’s PGA golf coverage just doesn’t add up

Golf telecasts are so larded with verbal filler that good visual stories are left unnoticed thus untold.

Saturday during The Players Championship on NBC, Dustin Johnson was about to hit to the do-or-dive, fish-surrounded par-3 17th when his caddy flashed three-fingers toward the TV camera behind the tee box. A graphic then appeared: Johnson would be hitting his 8-iron.

How did NBC know? Though many viewers already knew, many didn’t, thus it was worth a recorded show and tell.

When a TV-cooperative caddy shows two fingers, you add his five fingers to those flashed to make seven fingers, thus it’ll be a 7-iron. Same for 6-, 8- and 9-iron, whatever.

This would’ve made a nice insert as opposed to another on-camera session with Dan Hicks and Paul Azinger saying what could be said over live golf.

Does the pandering every stop?

Wednesday on TruTV before the Wright State-Bryant NCAA play-in game, analyst Steve Lavin described Bryant’s scoring star Peter Kiss, now nationally known for his obnoxious showboating and all-about-me demonstrations, as loaded with “personality.”

There was no mention that Kiss has spread his “personality” over three colleges. He previously played for Quinnipiac and Rutgers.

Bet on WFAN gambling promos

At what point do sports gambling enterprises run short of suckers?

All-news WCBS Radio 880, at 10:20 a.m. Tuesday, was sponsored by a sports betting operation.

The next day on all-gambling WFAN, an ad was heard for a sports gambling operation promising “better odds.” Really? If so, why no specifics? You’d think the operators would be eager to entice customers with “better odds.”

Good news for genuine fans of baseball on radio: Howie Rose, after rough surgery forced him to miss last year’s late season, will be back in the booth Saturday to call the Mets-Nationals exhibition.

The Spurs’ Gregg Popovich this week broke Don Nelson’s record for most NBA coaching wins. Pity Popovich insisted on being known as a miserable, condescending sourball.

NCAA Tournament CBS/Turner analyst Avery Johnson, a strong see-it/say-it observer of basketball, refers to wild 3-point attempts as “flying saucers.” Keeper!

Hey, Aaron Judge: Forget about next season’s contract and concentrate on laying off breaking balls thrown low and outside this season.

Toughest part of yesterday’s first-round NCAA coverage was locating truTV, then remembering the number. I kept landing on great deals for costume jewelry.

From ex-WFAN weekend man Chris Moore’s blog: “Ive a friend in Arizona who is a successful Uber driver because he has a good sense of Yuma.”