Couldas, wouldas and shouldas:

Ben Watson talked to ex-Saints teammate Jimmy Graham before and after Sunday’s game at Arizona.

Too bad they couldn’t converse while it was going on.

The Saints red-zone struggles were culprit No. 1 in the team’s 31-19 loss to the Cardinals, one that only emphasized the absence of Graham, now in Seattle after the All-Pro tight end was unexpectedly traded in March.

Of the Saints’ four times inside the Arizona 20, just one resulted in a touchdown.

It’s only one game, but that’s a far cry from the Saints’ 60 percent success rate of last season, which was fifth in the NFL. Of the team’s 39 touchdowns in 65 red-zone possessions (tied with Denver and New England for the most in the league), nine were by Graham, who had the same number in 2013.

“With Jimmy, we’d probably have thrown three fades in a row, and he’d have either caught it or gotten interference,” said Watson, who has succeeded his good friend as the starting tight end. “We had some good plays, but we didn’t execute them well enough to get into the end zone.”

Actually, once the Saints got close Sunday, there wasn’t much trying to get into end zone, or least not much trying to take the most direct route.

There were 10 offensive snaps from inside the 20, but just one was a throw into the end zone. That was the first one: a deep route to Brandin Cooks from the 19 that Patrick Peterson knocked away.

No disgrace there. Peterson’s on the fast track to the Hall of Fame.

But otherwise, it was succession of short routes, screens and runs that averaged picking up 3.3 yards. Even the 12-yard scoring reception by Brandon Coleman traveled only 2 yards downfield.

Watson, who wasn’t targeted on any of the red-zone plays, said he considers himself and all of the other backs and receivers to be scoring threats. But he added, “We can only run the plays that are called.”

Look for more variety in those plays this Sunday against Tampa Bay.

Saints coach Sean Payton, while acknowledging that Arizona has one of the league’s best red-zone defenses (the Cardinals were first in the NFC and third overall last year), said it was more than just the loss of Graham that made things so difficult.

“When you lose somebody like him, it’s not one player that replaces the touches,” Payton said. “Usually it’s a handful of players.

“When that takes place, you’ve got to find success. That’s something we will do, but there’s no magic wand.”

And it’s not just in the red zone.

The Saints looked more content to be horizontal than vertical on first and second downs Sunday, and they weren’t productive on those plays.

The result was that the team faced 18 third-down situations. Not only is that far more than last season’s average of 12.7, it was most since Game 15 of 2013.

“When you’ve had 17 or 18 third-down attempts, then typically you have not had the explosive play,” Payton said. “In the red zone, it makes for even more hard calls.”

One player who could see more attention this week is backup tight end Josh Hill. Hill, who averaged 12.6 yards-per-catch last year, wasn’t targeted Sunday.

One thing’s for certain: Jimmy Graham isn’t coming back.

Among all of the second guessing over the decision to punt with 1:58 left and two time outs left, has anyone considered this: Taking an intentional safety on first down from the 3.

There was 2:12 left, meaning the Saints could still stop the clock three times, so Arizona could run only a few seconds off the clock.

Plus, a free kick from the 20 would have pushed the Cardinals back to around their 20, not their 45 as it turned out, meaning a return punt would have put the Saints no worse than their 40 with plenty of time left.

And they’d still have been behind by only seven points.

Of course, that’s based on stopping the Cardinals, which the Saints didn’t.

Still, any alternative would have been better than what Payton did.

While 0-1 is not the place a team wants to start, considering the injury situation — which only got worse with Rafael Bush suffering a torn pectoral muscle — and the large number of first-year players and the quality of the opponent, it was pretty much to be expected.

Plus unlike last year’s opener against Atlanta, it wasn’t to a division foe.

Still, that makes the Tampa Bay game about as much of a must-win situation as a team can have this early.

Otherwise, as proved to be the case in 2014, 0-2 is a big hole to climb out of, even in the NFC South.