Recently it appeared the Seahawks were sending Richard Sherman a message by openly saying teams were talking to them about his availability in a trade. The apparent message: Be less tumultuous in 2017 than you were in 2016.

Now the message sender has become obvious.

It’s Sherman.

Amid the hubbub over Seattle general manager John Schneider being so oddly open on the radio Wednesday, saying reports about the team’s Sherman trade talks are “real,” this fact got lost: Not only is Sherman on board with Schneider’s public comments, Sherman wants to be traded.

There is no other logical explanation for the Seahawks being so transparent about shopping their three-time All-Pro cornerback to the highest possible bidder. The team’s coach and GM would breezily shoo away any trade questions — at least say “We don’t discuss internal matters” — if Sherman hadn’t already started talk of seeking a possible Seattle exit.

Coach Pete Carroll and Schneider have used the “internal matter” roadblock many times. In December, Carroll refused to answer whether he punished Sherman for berating offensive coordinator Darrell Bevell and him on the sideline over play calling during a win over Los Angeles. The coach called it, yes, an internal matter that would stay that way.

ESPN’s Adam Schefter came to the same conclusion, that the genesis of all this Sherman drama (which has replaced the now-ended Tony Romo saga in Dallas as the dominant story of this NFL offseason) is from the cornerback, not the Seahawks.

“It has been my understanding all along that Richard Sherman was the one who initiated this,” Schefter reported Friday. “He was the one that wanted to be traded initially. The Seahawks were obliging him and his request.”

Schneider would not be so transparent if Sherman didn’t ask for the team to explore how possible it is to deal him away. .

Thing is, the possibility of dealing Sherman is remote. Right now, anyway.

Yes, speculation — especially in April — is treacherous and usually foolish. But Schneider and the Seahawks have swung this door wide open.

First is what the Seahawks are likely to be asking for. Think: The moon. Maybe a few stars, too.

Think Pro Bowl-caliber starter with a contract more cap friendly than Sherman’s. Think high-round draft picks, the ones the commissioner — not a league operations assistant or NFL guest — announce.

Think New England’s second-team All-Pro cornerback Malcolm Butler. The Patriots are reportedly one of the teams that has asked about what it would take to acquire Sherman. Still asking, the Boston Globe reported this week amid conflicting stories from New England about that.

Problem there is the hero who intercepted Russell Wilson at the goal line to deny Seattle a second consecutive Super Bowl win recently received the first-round tender from the Patriots as a restricted free agent for 2017. Any team that wants to sign him would have to give New England a first-round pick.

Schneider’s in the market of acquiring high picks for Sherman here, not giving them — plus Seattle’s All-Pro cover man — away to create holes at both of the Seahawks’ cornerback spots this preseason.

Then there’s Sherman’s contract. It has two years remaining on the four-year, $56 million extension he signed in 2014. Sherman’s 2017 base pay of $11,431,000 is fully guaranteed. His salary-cap charge for this year is $13.63 million.

That would take up half or more of the cap space currently available for all but eight teams. The four that could afford him the most are the 49ers, Browns, Jaguars and Titans. Those four teams combined to go 15-49 last season.

Think Sherman would want a deal to San Francisco, Cleveland, Jacksonville or Tennessee? At age 29? At age 109?

We don’t, either.

But next year? Sherman’s so-called “dead money,” the cost against the cap should the Seahawks cut him loose, goes from $15.8 million to $2.2 million, and his scheduled base pay of $11 million is not guaranteed. That would be the time the Seahawks would have the most leverage for a rich deal. They’d have more competitive offers to trade him, to avoid him playing a final year of his contract at age 30. They’d know that unlike other potential suitors Seattle wasn’t going to give him another extension, at least not for anywhere near the cash he got in his last one.

Oh, yes, Sherman knows that in 2018 the Seahawks can cut him for just that $2 million cap charge, with an attractive cap savings of $11 million. That alone could be why he is searching for his way out of Seattle now, well before that could happen.

As Sherman said last week on ESPN: “It’s a business.”

All of this adds up to what Schneider said on KIRO AM Wednesday: “I don’t know if anything would ever happen.”

In the strong likelihood it doesn’t, Sherman wouldn’t be going anywhere but back into his blue-and-green No. 25 uniform. The Seahawks would be left with an All-Pro and Pro Bowl fixture starting at left cornerback for the seventh consecutive season.

But it would be the first season he, the Seahawks, you and the football world knew he is all for being out of Seattle.

So much for making 2017 with Sherman less tumultuous.