Mets' post-Deadline pitching staff: Who's new? What Q's remain?

NEW YORK -- In the estimation of Mets manager Carlos Mendoza, Luis Severino “just didn’t have it” Wednesday in an 8-3 loss to the Twins at Citi Field. Severino gave up six earned runs over only three innings. Worse, his fastball velocity dipped as low as 93 mph during a long third inning -- three ticks down from his season average.

Both Severino and Mendoza downplayed that issue after the game, with the pitcher saying he’ll find a way to fix it despite not being able “to go to the gym and do a couple push-ups and be back.” Jokes aside, in all likelihood, Severino’s velocity won’t be a lasting issue.

But it does speak to the tenuousness of Mets pitching even after the team traded for five arms prior to Tuesday’s Deadline. For this staff, questions still exist. Such as:

The rotation is deeper, but is it better?
Entering play Wednesday, the Mets ranked 17th in the Majors in rotation ERA at 4.18. The league average was 4.16. They ranked 18th in WHIP at 1.29 against a league average of 1.27. Their peripheral numbers -- including strikeout rate, walk rate and FIP -- suggest that if anything, their rotation has been a bit lucky. Either way, Mets starters were clearly a below-average unit even before Severino gave up a six-spot.

Paul Blackburn’s presence probably won’t change that. Over eight seasons with the A’s, Blackburn was a below-average starting pitcher himself, with a career league-adjusted ERA+ of 84 to prove it.

The Mets did not acquire Blackburn from the A’s to raise the ceiling of their rotation. If things go the way the Mets hope, Blackburn probably wouldn’t even be a consideration to start a playoff game. But he’s nonetheless important as a failsafe for the rest of this group, which includes:

• Severino, who held a 3.12 ERA over his first 13 starts but has since pitched to a 5.32 mark over his last eight. While Severino has done well to stay healthy this season, it has resulted in an innings total of 123 2/3, after the right-hander threw 209 1/3 over the past five seasons combined.
• Sean Manaea, who despite Tuesday’s strong start has been unable to complete five innings more often than he’s gone beyond six.
• Jose Quintana, who’s been the most consistent of the bunch but is 35 years old.
• David Peterson, whose walk rate of 4.36 batters per nine innings is 10th highest among 182 pitchers with at least 50 innings pitched.

Only three others stand anywhere near the Mets’ rotation equation right now: Kodai Senga, who’s almost certainly done for the regular season due to a strained left calf and has yet to address his situation publicly; Christian Scott, who is also out indefinitely with a sprained UCL in his right elbow; and Tylor Megill.

Megill on Wednesday received a temporary demotion to the bullpen, where he allowed one run over two innings in relief of Severino. He could receive another demotion to the Minors in the coming days, as Mets officials prefer to keep Megill stretched out as a starter rather than use him in an extended bullpen role à la José Buttó.

In the short term, the Mets appear to be choosing Blackburn over Megill. Longer-term, they’re going to have to figure out which pitchers from the above group can be viable playoff starters for them. They passed on the opportunity to spend significant prospect capital on a frontline type like Blake Snell, Garrett Crochet or Jack Flaherty. Which means they’re going to have to rely on a relatively middling group of starters, backed up by … a standout bullpen?

Does the “strength in numbers” relief model work?
Asked Tuesday if his bullpen philosophy revolves around collecting a large number of arms, as he did with the acquisition of six big league relievers in July alone, president of baseball operations David Stearns replied: “It’s probably quantity and quality if we’re doing this right.”

The Mets thought they possessed both entering Spring Training, but Edwin Díaz, Jake Diekman and Adam Ottavino -- three purportedly consistent veteran arms -- all struggled. Over time, the Mets designated Diekman and three other members of their Opening Day ’pen for assignment, while losing Brooks Raley, Drew Smith and prospect Nate Lavender to season-ending elbow surgeries.

As a result, casual fans may not recognize most faces these days when the bullpen doors swing open. The Mets certainly have quantity, thanks to a slew of trade acquisitions, one shrewd waiver claim in Alex Young, and some successful pop-up relievers from within the organization -- Buttó, Dedniel Núñez and the like.

But do they have enough quality? Time will tell, as the Mets determine over the next two months which relievers can be trusted in the biggest spots.

Or as Huascar Brazobán, one of the Mets’ Deadline additions, put it: “When you’re trying to push for a playoff spot, the games start to heighten, and it becomes a lot more exciting.”