So why aren't Mets spending like team with eyes on late October?

Just the facts:

● The Mets’ Opening Day payroll last season was a reported $101.3 million. They added another $8.3 million with three trades before the July 31 non-waiver deadline — and still spent less than their World Series opponent, the low-revenue Royals.

● The Mets earned at least $20 million in postseason revenue, according to the most conservative estimates. Their regular-season ratings on SportsNet New York (SNY) increased by 56 percent, according to Sports Business Daily. Their home attendance increased by 19.6 percent, with a comparable spike expected next season.

● The Mets have invested a combined $35.5 million on four free agents this offseason, or slightly less than what the Blue Jays gave free-agent left-hander J.A. Happ. They also added about $1.2 million in their trade of left-hander Jonathan Niese for second baseman Neil Walker — and saved up to $12.5 million with the retirement of outfielder Michael Cuddyer.

● The Mets’ commitments for 2016 are about $100.5 million for 16 players, including arbitration projections from MLBTradeRumors.com. Nine others — including starting pitchers Jacob deGrom, Noah Syndergaard and Steven Matz, catcher Travis d’Arnaud and left fielder Michael Conforto — figure to be at the $507,500 minimum salary or slightly above it. So, while general manager Sandy Alderson said recently that the payroll will be at “a higher level,” the best guess at the moment is not much higher.

And you want to know why Mets fans on Twitter freaked out Tuesday when news broke of the team’s agreement with free-agent outfielder Alejandro De Aza on a one-year, $5.75 million contract?

If the Mets are not going to spend big now — coming off a World Series appearance, with a crazy talented rotation that in ’16 will earn about $13.5 million combined — then they never will.

The Mets will say — accurately — that they’ve built a deeper roster of position players. They will say — accurately — that they again will possess financial flexibility at the non-waiver deadline.

But if the Mets truly were operating as a high-revenue, New York behemoth — not a team that seemingly is still haunted by the Madoff scandal — think of how much better they could be.

Remember, this is a team that in late July, pre-Yoenis Cespedes, ranked last in the NL in runs. The trade for Cespedes — combined with the emergence of Conforto, trade for Kelly Johnson and Juan Uribe, and return of David Wright — ignited the offense. Daniel Murphy, in particular, seemed to benefit from the improvements around him.

And now?

Murphy and Cespedes, the Mets’ 3-4 hitters in the postseason, are free-agent goners. The Walker-Cabrera combination might not be an upgrade over Murphy-Wilmer Flores. The De Aza-Juan Lagares platoon in center seems unlikely to make a significant impact.

The Mets can say — accurately — that few quality players were available at the positions where they needed the biggest improvements, shortstop and center field. They can also say — accurately — that they made a reported $60 million offer to free-agent everyman Ben Zobrist, only to lose him to the Cubs.

But imagine if the Mets did one more of the following:

● Signed a free-agent starting pitcher who would have provided the depth for a trade of a top young starter for a top young position player. 

● Solved shortstop by trading for Andrelton Simmons -- difficult, and maybe impossible, considering the Braves’ high asking price from a division opponent -- or signing free agent Ian Desmond, whose market is decidedly unclear. 

● Solved center field by signing free agent Dexter Fowler or acquiring the Rockies’ Carlos Gonzalez or Charlie Blackmon, with Lagares going elsewhere in a trade.

● Found power by replacing Cespedes — who, as a corner outfielder admittedly is a poor fit — by trading first baseman Lucas Duda and signing Chris Davis.

● Made an impact in the least expensive way possible by signing one of the many free-agent setup men who are now off the board — Darren O’Day, Ryan Madson, Joakim Soria, etc.

Those are just a few ideas, some better than others. Mets executives, if unshackled, probably could devise even more imaginative solutions. But gone is the promise that the front office showed with it bold moves at the deadline, the creativity, the aggressiveness.

Mets fans should be celebrating their favorite team’s first World Series appearance since 2000 and preparing for even better days ahead.

Instead, they’re pissed off.

ANOTHER LEFTY FOR DODGERS?

The Dodgers, in dire need of a right-handed starter, are interested in Japanese righty Kenta Maeda, as FOX Sports’ Jon Paul Morosi reported. But believe it or not, the team still is considering lefty starters, too.

Each of the Dodgers’ top four starters -- Clayton Kershaw, Hyun-Jin Ryu, Brett Anderson and Alex Wood -- is left-handed as right-hander Brandon McCarthy recovers from Tommy John surgery. The team’s top pitching prospect, Julio Urias, also is a lefty.

Still, none but Kershaw is a sure thing.

Ryu is coming off shoulder surgery. Anderson threw a career-high 180 1/3 innings last season after pitching only 206 1/3 the previous four. Wood could be a swingman or even a candidate for trade.

So, while the Dodgers explore both Maeda and the trade market, they’re also talking to free-agent lefty Scott Kazmir. Some rival executives even think they could be the team for former Orioles lefty Wei-Yin Chen, who reportedly wants a five-year, $100 million deal.

Chen, 30, holds particular appeal for analytics-minded clubs such as the Dodgers and Astros, one exec said. He had a combined 3.44 ERA the past two seasons pitching in the AL East at hitter-friendly Camden Yards. He has been on the disabled list in only one of his four major-league seasons, and that was due to an oblique strain. He also routinely outperforms his FIP (Fielding Independent Pitching) due in part to his ability to induce soft contact.

As if all that isn’t enough, Chen is the type of fly-ball pitcher who should thrive at Dodger Stadium. So, imagine if the Dodgers end up with Chen and Maeda, Kazmir and Maeda or even Chen and Rays righty Alex Cobb.

Wouldn’t be so bad, would it?

CUBS’ HEYWARD: ALL SET IN CENTER

The Cubs, recalling that Jorge Soler was one of their most dangerous hitters in the postseason, seem disinclined to trade him and clear right field for Jason Heyward.

Some rival executives say the Cubs will diminish Heyward’s impact by moving him from right to center, but the team takes a broader view of that issue, sources say.

The way the Cubs see it, Heyward’s offensive advantage over other center fielders should compensate for the difference if he is not as good in center defensively as he is in right.

Heyward had a .797 OPS last season. The major-league average in right field was .767, according to STATS LLC. The major-league average in center was .739.

In other words, Heyward is better than average offensively at both positions — and much better than average in center. So, if he could be even slightly above-average defensively for two or three seasons in center, all the better.

Trading Soler would force the Cubs to acquire or sign a center fielder, and for the moment they prefer to keep their assets — from Soler to infielder Javier Baez to pitcher Carl Edwards Jr. — rather than try to build the perfect roster, sources say.

The Cubs figure they can address any weakness later, whether it’s the back end of their rotation, their defense in the outfield corners, the depth of their bullpen. If they eventually trade Soler and return Heyward to right, Albert Almora could emerge as an internal solution in center.

NEXT FOR CARDINALS? PROBABLY NOT A TRADE

The Cardinals, after creating depth in their rotation with the addition of free-agent right-hander Mike Leake, do not plan to trade a pitcher for a hitter, sources say.

The team has taken that route twice in the past 13 months, sending righty Shelby Miller to the Braves for Heyward and left-handed prospect Rob Kaminsky to the Indians for first baseman Brandon Moss.

The return that the Braves received from the D-backs for Miller (five years of outfielder Ender Inciarte, and six each of pitching prospect Aaron Blair and shortstop Dansby Swanson) seemed far greater than what the Cardinals acquired with an extra year of control over Miller (one year of Heyward, two years of reliever Jordan Walden plus a draft pick.) But at the time, the Cardinals needed to find a replacement for the late Oscar Taveras, and Miller had not yet broken out.

The Cardinals, of course, still could sign a free-agent outfielder or even figure out a trade for one of the Rockies’ trio of Carlos Gonzalez, Charlie Blackmon and Corey Dickerson; the teams are engaged in dialogue, according to FOX Sports' Jon Paul Morosi.

But for now, the Cardinals believe their outfield will be better than expected. They remain high on Moss, who will be further removed from the hip surgery that he underwent in Oct. 2014. And they still see a healthy Matt Adams providing worthy competition at first — may the better left-handed hitter win.

AROUND THE HORN

● The Giants are considering all options for their outfield opening, but for the moment they seem more likely to make a trade or sign a lesser free agent than spend on a big-ticket item such as Cespedes or Justin Upton.

Free agents Gerardo Parra and Fowler are among the possibilities, sources say. Parra probably is a more natural fit, given his ability to play all three outfield positions — though, like Gregor Blanco, he is a left-handed hitter.

Fowler?

Well, the Giants still see Angel Pagan as their center fielder and leadoff man, but he’s coming off a career-low .635 OPS and will earn $10 million next season in the final year of his contract.

Perhaps the Giants could trade Pagan or sign Fowler to play left for one season, then return to center. Such a move would cost the team only a second-round draft pick (the Giants forfeited their first selection, No. 19 overall, with the signing of free-agent righty Jeff Samardzija).

Another option would be to find a right-handed platoon partner for Blanco, either through free agency or trade.

● If Samardzija can get $90 million on the open market coming off a disappointing season, what about fellow free-agent right-hander Mat Latos coming off his worst year?

The industry views the pitchers much differently, in part because teams regard Samardzija as a pitcher with superior makeup and Latos as almost the opposite. Still, Latos from 2010 to ’14 was no slouch.

During that period, Latos was one of five starters to produce an ERA under 3.50 for five straight seasons (minimum 100 innings each campaign). The others were Kershaw, Felix Hernandez, David Price and Madison Bumgarner.

Over the last 35 years, Latos and Tim Lincecum are the only two pitchers to start 30 or more games, throw 180 or more innings and strike out 180 or more hitters while producing sub-3.50 ERAs in four of their first five seasons.