The Post’s Jon Heyman delivers news and notes from around MLB:

Some Mets insiders say they believe Jacob deGrom isn’t bluffing when he says he will opt out of his deal, which guarantees $30.5 million next year. They believe that’s the case no matter his health status, too.

It’ll be an interesting call if he’s not close to 100 percent (the most recent MRI exam was encouraging, however). The Mets made not try to extend him in the winter, even before the latest shoulder worry.

That the Mets are 14-6 without deGrom is a testament to their unusual pitching depth — Tylor Megill, David Peterson and Carlos Carrasco have all outperformed.

Kumar Rocker is readying for independent ball as he hopes to make an impression for the 2022 MLB draft.

Good thing the Padres didn’t trade Eric Hosmer, who entered Thursday leading MLB with a .410 batting average.

Big starts for two backup plans to Freddie Freeman. Matt Olson (MLB-leading nine doubles) and Anthony Rizzo (MLB-leading eight HRs).

Brett Gardner had opportunities to play elsewhere but apparently only wants to be a Yankee.

The Yankees’ letter turned out to be next to nothing. Still not quite sure why they fought so hard to try to keep it concealed. … The Angels check with their players regularly, and the great Shohei Ohtani, despite having two jobs, hasn’t wanted to miss a day yet.

Can’t blame Myles Straw for defending his Guardians teammate Steven Kwan, who didn’t need to hear verbal abuse after running into the wall and needing a concussion check (he didn’t have one, thankfully). I don’t care what the tapes said later, there’s no excuse for throwing garbage at Straw. … Owen Miller (1.300 OPS) has been a revelation in Cleveland.

Julio Urias is on his game, and he’s back up to 94 mph, as the Dodgers roll along … The Nationals-owning Lerners are taking bids, and seem likely to be sold. … Cole Hamels is targeting June-July for a possible showcase.

Reds COO Phil Castellini’s apology letter to employees regarding his dismissive public challenge to Reds fans to find something else to do in Cincinnati following their fire sale — “What are they gonna do?” — didn’t do much to assuage employees dismayed by the player sell-off, plus meager employee raises and recent removal from the non-uniform pension (many teams did that).

The Reds were hit harder than most teams by financial reverses due to COVID, as they depend on gate receipts more than TV. Anyway, there were a decent number of resignations (one person thought 30) before even hearing the apology, first reported by The Post. The Reds maintain the number of resignations is lower than that.

Reds ownership made fans remove a “Sell the team” banner. Bags are currently warranted, however, with a recent nine-game losing streak in which they scored no more than two runs each game — not really a development considering the extreme sell-off combined with 14 players on the IL

The way the team’s going, combined with a run of rough contracts by the previous regime (Mike Moustakas, Shogo Akiyama, Eugenio Suarez, Homer Bailey, the opt-out for Nick Castellanos) could bring some change. But what change? The COO is the son of the owner, the manager is the son of Cincinnati legend Buddy Bell, who also happens to be the owner’s BFF. One rumor has former GM Walt Jocketty, currently a consultant, taking on a somewhat bigger role, but who knows if he’d even want that?

Castellanos told Barry Jackson of the Miami Herald he believed he would have gone home to the Marlins if Derek Jeter was still there (they’d been talking about a five-year deal). … It’s still hard to believe Jeter left only because they were just able to sign Avisail Garcia (and ultimately Jorge Soler) and not the somewhat pricier Castellanos, as has been suggested. Word also is owner Bruce Sherman was unhappy with continuing financial setbacks. … Anyway, GM Kim Ng was put in total charge, and it’s an open question what will happen to Jeter’s righthand man Gary Denbo, who hired almost all the directors but has since turned off a few with his unbridled intensity.

Willson Contreras still looks like a trade candidate in July with Yan Gomes in reserve … The Diamondacks have two veteran closers in Mark Melancon and Ian Kennedy, giving them two trade chips.

Player of the Week: Byron Buxton, Twins; Runners-up: Mike Trout, Angels. Walker Buehler, Dodgers; Cody Bellinger, Dodgers; Connor Joe, Rockies; Ty France, Mariners.

Felix Hernandez, not only a great pitcher but great personality, is spending his time coaching son Jeremy’s 14U team and presumably retired, according to Miami friends. He hasn’t announced anything but didn’t play winter ball after missing last year following an injury late in what looked like a big comeback spring for him. His Hall of Fame candidacy would look a lot like Johan Santana’s. Santana was eliminated on the first ballot, unfortunately. Time to be rid of that 5 percent rule. … Congrats also to fellow Miamian Jon Jay, who retired and has been taking classes to finish his degree at The U.