The Mets will announce shortly after the season that general manager Omar Minaya and manager Jerry Manuel won’t be returning in their roles, sources say. The announcements are likely to be made before the playoffs begin Wednesday. The changes will not come as a surprise, as they have been widely assumed for a few weeks now.

It isn’t expected that either replacement will be named immediately. There’s no evidence the Mets have begun contacting GM candidates. The new GM is expected to have a big say in the hiring of a new manager, so the managerial position will remain vacant for a period, as well.

– Jon Heyman, SI.com.

Not exactly shocking news here, but perhaps the most definitively written of the anonymously sourced stories we’ve seen so far suggesting that both Minaya and Manuel will be gone after the season, since Heyman’s report includes at least vague, measured details about what exactly will happen to Minaya and the money owed him.

As I mentioned here earlier, the speculation around what will happen with the Mets’ front office and bench has grown tiresome, especially considering how much clearer the picture will likely look in just a few days. And it’s a bit frustrating because, if these stories are true, it’s unclear why the Mets feel the need to wait until the end of the regular season to part ways with their general manager and field manager.

I wrote this last year:

I always take offseason rumors from anonymous sources with several grains of salt, but what Heyman suggests does seem to jive with everything that has happened in the Mets’ front office and every rumor we’ve heard.

And if it’s really true, the Mets should fire Omar Minaya right now.

Look: Either you have confidence in a GM to build your team for the upcoming season and the future or you don’t. “Putting the heat on him,” as has been suggested, is about the worst possible approach. That only further pushes Minaya toward moves of desperation, the type made to save his job but not necessarily to forward the franchise.

For whatever reason — bureaucracy, checks on Minaya’s power, who knows? — the Mets managed to make it through 2010 without doing major damage to their future. But there were plenty of assignments and transactions that may have negatively impacted that outlook, and as far as I’m concerned, a team should just never go forward entrusting important decisions to people whom it no longer trusts are best fit to make them.

Presumably the Mets will get a fresh start soon, with someone helming baseball decisions and, eventually, a manager they feel can aptly run their team in 2011 and beyond. But if they didn’t feel confident that Minaya and Manuel were the guys to do that entering 2010, it’s puzzling why they kept them around so long.

So, take Beltran’s xBABIP for this year, and add back in those six hits he lost to luck – call them all singles – and you have a .280/.367/.459 line, or a .352 wOBA. Combined with scratch defense in the corner outfield, and that’s something like a 3 WAR player over a full year. Not exactly a cheap player, given that wins are about $4-5 million per, but not grossly overpaid either. Does it seem worth paying another team most of that salary to get off the team? Probably not….

Lastly, Beltran does have better upside. He might just be better than a scratch right fielder with an offseason of preparation and recuperation. If we use his UZR instead of UZR/150 (-3), then we actually get a +7 defensive right fielder, and closer to a four-win player. Beltran has surpassed that number in every full, healthy year but two in his career. Can Duda, Murphy and Evans get you four wins? Probably (definitely?) not.

– Eno Sarris, Amazin’ Avenue.

Sarris takes time away from slandering Ruben Tejada to pen a nice piece examining the positives and negatives of trading Beltran, something I’ve been doing a bit here lately and something it sure sounds like the Mets will be doing this offseason.

Look: All of this speculation hinges on the terms of the deal. Sarris assumes — as I have, as many have — that the Mets will have to eat a huge portion of Beltran’s contract just to be rid of him, and that they won’t get much back in terms of talent. But sometimes everyone figures one thing and then something else entirely happens, and so maybe there’s some total sucker out there willing to take on all of Beltran’s contract and give the Mets something valuable in return, in which case, you know, I’ll miss you Carlos Beltran but, well, peace out.

I doubt that’s the case, though, so for the sake of the below exercise let’s go on assuming what we have been assuming. So do the various potential positives of dealing him outweigh the potential positives of keeping him?

Dealing him means likely somewhere between $3-5 million of salary relief. That’s a positive for a cash-strapped team, inarguably. It also brings a variety of nebulous positives probably don’t matter in the win column: a “new image” for the club, the establishment of different clubhouse leaders, whatever.

In Lucas Duda, Nick Evans and Daniel Murphy, the team has corner-outfield types who appear at least close to Major League ready, so it’s not that the team would immediately have to go about appropriating the money saved by dealing Beltran to replacing Beltran. More likely, it could be spent on pitching or middle infield help, more glaring needs.

But, as Sarris suggests, no combination of those three is likely to match the contributions of a healthy Beltran, which leads me to the major positive of not dealing Beltran: You get to have Carlos Beltran on your team.

The issue, of course, is that it’s far from guaranteed that Beltran will be able to stay on the field or produce anything like the way he did from 2006 to 2008, when he was one of the very best players in baseball.

But essentially, in some convoluted way — and again, assuming the Mets have to eat a lot of money just to move Beltran — it works out to taking a $3-5 million gamble that Beltran can remain mostly healthy and productive for the 2011 season. Given the potential upside, that seems like a worthwhile risk.