The Mets’ rotation addition has, at least for the time being, led to a bullpen addition.

With Paul Blackburn expected to join the rotation to begin Friday’s series in Anaheim, Tylor Megill has been bumped to a relief role for the moment.

Megill was set to be available out of the bullpen Wednesday, Carlos Mendoza said, with the Mets opting for a five-man rotation at this time likely in part because they have an off day Thursday.

They play 10 straight days beginning Friday.

“We got a decision to make [in the days coming up], whether we’re going to go to six-man,” the manager said before the series finale against the Twins at Citi Field. “We’ve got to get through today and then see what we got there.”

On Tuesday, the Mets traded for the A’s Blackburn, a veteran who returned from the injured list Friday and allowed four runs in five innings to the Angels.

The 30-year-old will join the Mets in California and slot into a rotation that has lost Kodai Senga and Christian Scott.  

It might be losing Megill, too, depending upon the rotation’s health and Megill’s effectiveness out of the bullpen. The 29-year-old has again tantalized with his pure stuff this season and again not turned that stuff into consistent results, with a 5.20 ERA in nine starts.

The big righty has occasionally been used out the pen in the past and always has seemed like a good candidate to see an uptick in success and stuff when used in shorter bursts.

But the plan at least for the moment is to keep Megill stretched out so he still could slot into the rotation.

“We see him as a starter, but then we also can see him going in the bullpen for now,” Mendoza said. “He might throw 100 [mph] there, the velo is there and he’s got so many pitches and weapons. So if you’re shooting for an inning or two, I think it comes down to how well he bounces back after an outing or two.

“But big picture, we see him as a starter.”