The Mets’ season-long strength suddenly does not seem as strong.

For seventy and a half days, amidst inconsistent outcomes from an on-and-offense, the Mets have found reassurance in a seemingly endless supply of starting pitchers.

It’s not only that the starting rotation has been reliable, but also deep enough to withstand setbacks like those experienced by Sean Manaea and Frankie Montas, and swiftly recover from them.

However, in a short period of seventy-two hours, the Mets faced a series of challenges: 1) Kodai Senga’s absence due to a hamstring strain sustained on Thursday, likely sidelining him for at least a month; 2) uncertainty surrounding a potential replacement in Montas, who is not guaranteed a spot in the rotation mainly due to his lackluster performance in five rehab starts, culminating in a disastrous outing on Friday; and 3) growing concerns regarding Tylor Megill’s form.

Because on Saturday, the struggles of the No. 5 starter continued in an 8-4 loss to the Rays in front of 41,662 rain-soaked fans at Citi Field, where the Mets dropped a series — snapping a streak of six series they either won or tied — before Sunday’s finale.

The Mets (45-26) do not need brilliance from Megill, but they need more than he provided while pitching 3 ²/₃ innings and allowing six runs (three earned), lowlighted by a fourth inning that included the big righty hearing boos as he was pulled from the start.

In that inning, the Rays sent 11 batters to the plate — 10 against Megill — and a Mets lead evaporated instantly.

The first batter, Junior Caminero, destroyed a 2-1 sinker 409 feet to left, deep into the first deck to tie the game.

After two more Rays reached — a plunking and a single to put runners on the corners — the frame turned on a rare safety squeeze from Taylor Walls, who dragged a bunt toward first base.

Megill ignored a potential play at home and tried to go to first but dropped the ball as he cocked it behind him.

Megill struck out Josh Lowe which, because of his own error, was crucially only the second out of the inning. Given life, the Rays attempted to put down the Mets with a pair of RBI singles, a seven-pitch walk to Jonathan Aranda to reload the bases, and a wild pitch that put the Mets in a 6-2 hole.

After Megill lost Caminero, the inning’s leadoff hitter, to a seven-pitch walk, Carlos Mendoza took the ball from him, and boos followed a head-down Megill every step to the dugout.

It is possible that Megill did not bounce back well from his most recent start at Coors Field — where the altitude affected Friday’s starter, Clay Holmes, and prompted a shorter start — but the troubling trend lines extend further than last week.

Six starts into his season, Megill looked like a breakout candidate and owned a 1.74 ERA.

In eight starts since the beginning of May, he has pitched to a 5.79 ERA that has elevated his season mark to 3.95.

It is possible Montas replaces Megill eventually, but the Mets are not sure what to do with the offseason addition who has been knocked around during a rehab assignment and will require a sixth minor league start.

The loss of Senga has meant Paul Blackburn, who was crushed in relief Friday, is at least temporarily back into the starting group.

For a group that has rolled really from Day One, a speed bump has appeared.

Buried in the fourth inning, the Mets did not have enough offense to overcome the hole.

They cut the lead to four runs and put runners on the corners in both the seventh and eighth innings, but a Brandon Nimmo ground out and Brett Baty ground out, respectively, helped the Rays navigate out of danger.

Wasted was the hardest struck ball by a Mets player all season — a laser, 115.6 mph home run to right field by Brett Baty that also was the hardest hit ball of Baty’s major league career — along with the second home run of Ronny Mauricio’s season and three hits (including two RBI singles) from Nimmo.

Also wasted was a tour de force from Luis Torrens’ arm, which threw out Josh Lowe at second base and Walls in the fifth inning. In the sixth, Torrens chased a wild pitch to the backstop and threw a strike to José Buttó, who tagged out Yandy Díaz trying to score from third.