With Trevor Rosenthal no longer an option, will the A’s pursue a closer at the trade deadline?

The A’s spent $11 million on Trevor Rosenthal with hope that the highly-regarded free agent would replace Liam Hendriks’ production as closer and anchor Oakland’s bullpen. But Rosenthal will not throw a single pitch with the A’s this season after undergoing back-to-back surgeries for his Thoracic Outlet syndrome in April and then a season-ending procedure for a torn labrum on Tuesday.

Before the hip injury cropped up, Oakland hoped Rosenthal could slide into the closer spot mid-August to give the bullpen a boost down the stretch. Now, the A’s will need to stick with the closers that stepped up, or look for a new one on the market.

“It stings. This was kind of the final piece we brought in when some money was freed up to bring in a guy like him and expect him to be your closer,” Manager Bob Melvin said. “It’s disappointing, it’s disappointing for him, too. He wanted to pitch for us. When he had his shoulder surgery he worked hard to try to come back, we were targeting middle of August for him and this popped up.”

What will the A’s do?

Most likely scenario: Stick with Lou Trivino and add other bullpen pieces

Not only has Lou Trivino bounced back from his 2019 low, he’s a more complete pitcher as the A’s closer. Chances are the A’s will stick with Trivino in the ninth inning.

Trivino is throwing his changeup and curveball more often with more confidence and his cutter is regaining the levels of cut that made him a dominant set-up man in 2018. Trivino could take another step if his cutter can get back to the 38% whiff rate he had in 2018 (when he threw the pitch primarily). Even if Trivino isn’t missing as many bats, he’s missing barrels, and that’s helped him to a 1.96 ERA over 40 appearances this year. He allowed just one run in June, on the last day.

“We’ve been operating the way we have been and that’s the way we’ll keep going, and we’ll see what happens around the trade deadline,” Melvin said. “But what we have is what we have now and that’s what we’ve been operating with the entire year.”

As the only left-handed option other than Sam Moll out of the bullpen, Jake Diekman, has also pitched in the ninth inning when matchups have dictated it. He has the stuff to close, but his role as a left-handed option in any high-pressure situation trumps all.

The A’s may not target a Rosenthal-esque closer, but they’ll almost certainly keep adding bullpen arms on cheaper contracts. Depth is lacking on the pitching staff with Jesús Luzardo and A.J. Puk figuring things out in Triple-A, so the A’s almost certainly will target another left-handed option and search for some unpolished gems to create more depth on the pitching front for the second half.

Less-likely scenario: Trade for a closer

Closers will be available at the trade deadline, and rumors have linked Chicago Cubs closer Craig Kimbrel with the A’s and Houston Astros.

Kimbrel, though, is owed $16 million in 2022 before becoming a free agent, and the A’s might not have the prospects in their 28th-ranked farm system, let alone spending capacity, to target the 33-year-old closer.

Minnesota Twins scouts have recently been spotted at the A’s High-A affiliate Lansing Lugnuts games. The Twins are underperforming in fourth place in the AL Central with a 36-50 record. Their late-inning right-handed reliever Taylor Rogers could be on the block and A’s radar. Rogers, 30, has a 2.45 ERA in 35 games.

Hendriks was the A’s most valuable asset in the postseason and in high-leverage situations in 2020 and 2019. If the A’s feel they need more of a sure thing, go-to reliever in any match-up against the game’s best hitters, they may prioritize getting a guy they hoped Rosenthal could be. Nothing is out of the realm of possibility for the A’s as they navigate a tight division race with the Astros.

Alternate possibility: Call up some prospects

Miguel Romero and Wandisson Charles could be options for call-ups as late-inning relief options. But both are struggling this year with Triple-A Las Vegas.

Romero, 27, has back-end bullpen stuff but a 8.10 ERA in 16 appearances. Charles has struggled to stay healty all season.