The Wilpons must raise their payroll for 2020.

They surely want to hear that as much as Art Howe is returning as manager, Al Harazin as GM and Bernie Madoff as chief financial officer.

But if the Mets want to contend next year — and they do — then it is going to be hard to construct a playoff roster without lifting the payroll. Consider:

1. They began last season with a $158 million payroll. That included $44 million for Yoenis Cespedes and David Wright, though neither played an inning and the Mets reportedly got back 75 percent in insurance minus premium costs.

2. They currently have $129 million for 2020 with Cespedes, Wright, Robinson Cano (minus the $3.75 million paid by Seattle), Jacob deGrom (plus the $10 million part of his signing bonus due in January), Jed Lowrie, Wilson Ramos and Justin Wilson. Wright is not playing in 2020 and who knows what the Mets can expect from Cespedes, except that if he is on the active roster there will be no insurance payouts.

3. Edwin Diaz and Seth Lugo, in particular, have huge potential swings in what they could earn via their first season of arbitration eligibility. But an expert who works on the process provided a rough arbitration budget for those two plus Marcus Stroman, Noah Syndergaard, Michael Conforto, Robert Gsellman and Brandon Nimmo at $40 million to $45 million. Let’s call it $42 million, which puts the Mets at $171 million before discussing Zack Wheeler or his replacement, bullpen reinforcements and if another run at Yasmani Grandal will be made.

The Mets could trade Diaz and/or Syndergaard for low-cost returns, but they would be doing so with both talents at a value low point after disappointing seasons. Also, they would need to find replacements, which especially with starters can get expensive.

5. And the Mets have to be careful about how quickly their rotation strength could dissipate. They will probably qualify Zack Wheeler (around $18 million), he will likely reject and the Mets’ chance to get him at a discount is gone. His baseline is probably four years at $60 million, but I have talked to outside executives who think that can go to $75 million or higher based on Wheeler’s talent and durability the past two years.

So either add Wheeler to that running payroll meter or figure out how to replace him. Stroman is a free agent after the 2020 season, Syndergaard and Steven Matz after 2021. And three of the Mets’ better pitching prospects went in trades for Cano/Diaz and Stroman, including Justin Dunn and Anthony Kay, who would have been at least depth pieces next year.

6. The Mets might have to re-allocate from one area to cover another. For example, Red Sox ownership has said it wants to stay under the $208 million luxury-tax threshold next year, which entails real pruning. If the Mets lost Wheeler, would it make sense for them to try to obtain Nathan Eovaldi (who has three years at $51 million left) for Wilson Ramos and Jed Lowrie ($21.75 million left)?

For tax purposes, Eovaldi costs $17 million next year, and Ramos and Lowrie are a combined $19.5 million, but for the Red Sox, it would not just be removing Eovaldi’s future cash, but also Ramos could replace Sandy Leon as the backup catcher and assume part of the DH if J.D. Martinez opted out while Lowrie could replace free agent second baseman Brock Holt. That would open catcher for the Mets to pursue Grandal, but — of course — that would mean a real hike in 2020 payroll.

7. And why approve that expansion? Because how many more great seasons do they think deGrom has left? Time will soon expire on having Pete Alonso and Jeff McNeil for a relative pittance.

8. The Wilpons should do a two-year payroll then empower Brodie Van Wagenen to divvy up how much he wants to allocate for each season. Because he could go higher next year with the promise of lower the following season when Cespedes, Wright, Stroman, Ramos, Lowrie and Wilson will be free.

9. This is going to be a tough financial needle to thread, and ownership is going to have to be disciplined and defined. The Wilpons’ pattern is to create an overall budget, which means including the debt service on Citi Field. That’s one reason the payroll is tighter than what a big-market organization with a massive fan base should spend.

Conversely, the Wilpons will allow flexibility as the offseason arises. But both Fred and Jeff must be convinced, they often do not agree and they both have their own baseball convictions — Fred’s, for example, rooted in a more old-school non-analytic belief system. This is not the offseason for lack of unity or for a tight belt. Aside from Grandal, the Mets should be adding no other long-term free agent pacts. But to contend in 2020, the Mets are going to have to augment and deepen with one-year deals and that is going to come with a price for next season that ownership has to bless.