Billy Eppler’s offseason strategy with the Mets bullpen centered on adding three proven arms to the roster and filling the other vacancies with quantity over track record.

That meant augmenting David Robertson, Adam Ottavino and Brooks Raley with relievers who had minor-league options remaining or were low-risk free agents who could be shuttled between Triple-A Syracuse and the Mets depending on need, bringing flexibility to the bullpen and ensuring there’s always a fresh arm nearby.

But that system is dependent on finding the right pieces, and to this point the returns haven’t been great for Eppler.

Jeff Brigham, acquired in a trade with the Marlins, has been a solid piece to the bullpen for much of the season, but relievers such as Stephen Nogosek, Jimmy Yacabonis, John Curtiss and Dennis Santana — utilized at various points — haven’t been as consistent.

Nogosek was designated for assignment last weekend and refused an outright assignment to Syracuse to become a free agent.

In assessing the Mets’ choices following Drew Smith’s 10-game suspension that began Wednesday for violating MLB’s rules on foreign substances, manager Buck Showalter mentioned the importance of optionable relievers to help fill the void.

The Mets won’t be allowed to replace Smith on the roster, leaving the bullpen at seven.

But relievers such as Curtiss and Josh Walker can be optioned to Syracuse, effectively allowing the Mets to bring in fresh arms as needed. It’s not ideal because pitchers have to remain in the minors for 15 days after they are sent down unless there is an IL stint as the corresponding move.

There is still hope for Eppler’s bullpen plan that goes beyond banking on better results from the relievers who have appeared in games for the Mets this season.

The names to watch include Stephen Ridings, Sean Reid-Foley and Sam Coonrod, all of whom are returning from injuries.

Ridings, a Long Island native who appeared in five games for the Yankees in 2021, is the closest to ready after he was reinstated from his minor-league rehab assignment and optioned to Syracuse on Thursday.

The right-hander’s 100-mph heat created a buzz early in spring training — pitching coach Jeremy Hefner at one point called Ridings’ stuff the best he had seen in camp — but his injury history is long. The Mets purposefully took it slow with Ridings with the hope he could contribute in the second half.

Reid-Foley is nearing a rehab assignment after undergoing Tommy John surgery last May. The right-hander, who arrived as part of the trade that sent Steven Matz to Toronto, was effective for the Mets in the first half of the 2021 season.

Coonrod, signed as a minor-league free agent in the offseason, was in strong position to claim a spot on the Opening Day roster before a high-grade lat strain sidelined him. The right-hander has just begun ramping up toward a return.

Want to catch a game? The Mets schedule with links to buy tickets can be found here.

Daniel Vogelbach’s season took a strange turn in the last week, with the DH receiving a mental break to work on his swing, during which time he remained on the active roster but was withheld from playing by Showalter.

Many organizations already might have moved on from the underperforming Vogelbach, who is earning only $1.5 million this season. But Mets officials view Vogelbach’s on-base percentage and penchant for hitting the ball hard as assets that shouldn’t easily be discarded.

Vogelbach is likely facing his last chance with the Mets in the coming weeks. If the team wanted to create goodwill with much of the fan base, it might have signed Daniel Murphy and at least given him a look at Triple-A Syracuse as a potential lefty bat replacement for Vogelbach should his struggles persist.

Murphy, who was playing for the Long Island Ducks, was signed to a minor-league contract by the Angels this week.

The Mets have options in the right-handed DH role — Tommy Pham and Mark Vientos among them — but there isn’t an obvious left-handed bat if Vogelbach can’t produce. It could lead to employing Francisco Alvarez as the DH more than the Mets would ideally like, with Omar Narvaez behind the plate.

We’ll use this space to mention that Michael Conforto was among the players the Mets passed on last offseason. Conforto owns a .790 OPS with 12 homers for the Giants.

Pete Alonso is an All-Star if he’s healthy, but otherwise it’s hard to establish an overwhelming All-Star case for anybody on the Mets roster, which isn’t a good sign for a team with a record $370 million payroll.

Brandon Nimmo hasn’t disappointed and may ultimately get the call for the July 11 Midsummer Classic in Seattle if Alonso still hasn’t returned from the injured list, but there are plenty of worthy NL outfielders ahead of him, including Ronald Acuña Jr., Mookie Betts, Corbin Carroll, Juan Soto and Fernando Tatis Jr.

Before spring training started, you would have tabbed Alonso, Francisco Lindor, Jeff McNeil, Justin Verlander, Max Scherzer and Edwin Diaz as the likely All-Star candidates from the Mets, but the majority of that group has been disappointing and Diaz hasn’t thrown a pitch as he rehabs from surgery to repair the patellar tendon in his right knee.

Robertson’s numbers have been strong as Diaz’s replacement, and he certainly could be considered as an All-Star selection.

Alvarez’s candidacy might look better as he builds up at-bats in the next few weeks. The rookie catcher had a great May after struggling in April. June has been tough: He has a .689 OPS for the month, though four of his seven hits have been homers.

Alonso’s bone bruise and sprained wrist that ultimately could cost him a month hurts the Mets lineup, but also eliminates any realistic possibility the slugging first baseman will chase 60 homers this season.

Alonso blasted 22 homers in his first 62 games, putting him on pace for 57. In a best-case scenario, Alonso can return before the All-Star break and chase 50 homers.

Two energized sellout crowds at Citi Field this week proved the Subway Series still has plenty of juice. Expect two more such crowds at Yankee Stadium in July.

The days of the Subway rivals meeting six times in a regular season — something that occurred every third year under MLB’s previous scheduling system — are over. The expanded slate of interleague games and reduced division schedule means there’s room for just four Subway Series games each season.

No complaints here. Increasing from four to six games every third year was probably overkill, but four consistently seems just right.