The Oakland A’s are on the brink of running out of starting pitchers, having lost more than a full rotation’s worth to injury already by June. Fortunately the bullpen is not experiencing the same problem, and in fact they have so many relief arms on the depth chart that a couple of particularly promising ones are temporarily blocked from reaching MLB.

The relievers can be organized into three main tiers: the entrenched MLB arms, the taxi squad, and the non-roster depth. Pitchers in the first category might be there because of how indispensably good they are, and/or because their contract status won’t allow them to be optioned to the minors. They include:

Blake Treinen

Lou Trivino

Yusmeiro Petit

Santiago Casilla

Chris Hatcher

Liam Hendriks

Ryan Buchter (DL)

Treinen and Trivino technically have minor league options, but they are the two best arms in the pen and they own the 8th and 9th innings; Treinen might even make the All-Star team. Buchter is in the same boat, as by far the best lefty on the club. Meanwhile, Petit and Casilla are on MLB free agent contracts, and Hatcher and Hendriks are out of options. Whether those last three names should be kept around will be addressed later, but the point for now is they can’t simply be sent down.

Next up is the taxi squad, consisting of pitchers on the 40-man roster who have options remaining and thus move up and down to Triple-A as needed. All of them have seen time in Oakland this year and a couple are there right now (Pagan and Lucas), but none have stood out enough to ascend to the first group like Trivino:

Emilio Pagan

Ryan Dull

Daniel Coulombe

Josh Lucas

Carlos Ramirez

And finally, the best of the rest. These guys aren’t on the 40-man roster, but they are standing out in Triple-A and seem like they could be possibilities down the road. Most of them have also appeared in MLB during their careers:

Bobby Wahl

J.B. Wendelken

Jake Sanchez

Dean Kiekhefer

Jeremy Bleich

There’s also Raul Alcantara, but he isn’t thriving as hoped in shorter stints. Kyle Finnegan and his elite velocity are on the disabled list. Here’s a quick rundown of the five names above:

Wahl: 2.89 ERA, 28 ip, 42 Ks, 15 BB, 1 HR, 16 hits, 2.97 FIP

He made our Community Prospect List four times before finally debuting in MLB last year. He has a power arsenal with an upper-90s fastball and a slider, but he’s often struggled with control and he gets injured just about every year. He’s been healthy and brilliant this season at age 26, though he got lit up in each of his last three games (total: 2 ip, 7 runs, 4 ER, 2 Ks, 6 BB, 4 hits).

Wendelken: 3.32 ERA, 19 ip, 29 Ks, 7 BB, 1 HR, 16 hits, 2.53 FIP

After being acquired for Brett Lawrie, he made our pre-2016 CPL and then debuted that summer. He missed 2017 due to Tommy John surgery, but now he’s back at age 25 and piling up strikeouts again. Add in his Double-A numbers and he’s fanned 52 in 31⅓ innings, a full 36.9% of the batters he’s faced. His primary weapon is a devastating changeup.

Sanchez: 3.57 ERA, 22⅔ ip, 22 Ks, 4 BB, 2 HR, 23 hits, 3.79 FIP

Trivino’s path is what we hoped Sanchez would do, and it still could be. He’s another failed starter who reached back for top-notch velocity in short stints, but after showing flashes of dominance in the upper minors he got hurt last year. Now he appears to be healthy and back in the picture at age 28.

Kiekhefer: 4.26 ERA, 12⅔ ip, 15 Ks, 0 BB, 0 HR, 19 hits, 1.66 FIP

Bleich: 2.67 ERA, 30⅓ ip, 29 Ks, 7 BB, 2 HR, 26 hits, 3.43 FIP

These two profile as org filler more than anything else, but they’re lefties and that makes them relevant. Buchter should be back in action soon from his injury, but after him the southpaw depth chart is just Coulombe and whoever happens to be on the waiver wire that week. Kiekhefer, a 29-year-old sidearming soft-tosser, hasn’t walked any of the 57 batters he’s faced in Triple-A. Bleich throws harder and has some interesting backstory, but he’s more than a decade into his pro career and hasn’t yet reached the bigs; he’ll turn 31 tomorrow.

All told, once Buchter returns (maybe next week?), the A’s roster will include 12 relievers for eight spots. After that there are three more imminently enticing righties in Nashville, and a pair of potentially viable lefties. Wahl and Wendelken in particular have nothing left to prove in the minors, and now that they’re healthy they appear as ready as they’ll ever be for their next MLB chances. And all of this is before considering the futures of Andrew Triggs and Brett Anderson, two injured starters who would make a lot of sense in the bullpen for the rest of the summer.

With all this depth mounting in Triple-A, how much longer do the A’s need to hold onto the weak links on the current MLB roster? Casilla and Hatcher look good in the ERA department, but Casilla is using BABIP luck to get around an absurd walk rate and Hatcher is doing most of his work in garbage time while himself navigating around a shaky 5.07 FIP. Their usage patterns clearly illustrate the team’s lack of faith in them. Carrying them in the beginning of the season made sense because you never know how many injuries you’ll need to cover for, but we’re approaching the halfway point and the coast looks clear on that front.

What’s the upside to keeping Casilla and Hatcher? Even if the A’s did suffer a rash of five or more bullpen injuries right now, their presence wouldn’t exactly save the day or sustain a surprise postseason run. It’s difficult to see them having any relevant trade value, nor for either to be here next season — Casilla is a free agent and Hatcher will cost more than he’s worth in his final year of arbitration. On the other hand, they reduce the roster’s flexibility by being relievers who can’t be trusted in the late innings but also can’t be swapped down to the minors when fresh arms are needed.

It’s time to start seriously considering the next phase of the 2018 bullpen. The new wave of reinforcements is beyond ready, and there’s no longer the need for the A’s to go out of their way to keep fringey depth locked into the roster. Casilla and Hatcher have gone from being potentially useful backups to blocking the promising arms who should be auditioning for 2019. Free Wahl and Wendelken!

Starters apply here

With the A’s reaching down as far as the 13th starter on their preseason depth chart, there’s not much left in the cupboard in Triple-A. Oakland’s current rotation includes Manaea, Mengden, Blackburn, Montas, and Bassitt, and the injury list features Graveman, Cotton, Gossett, Triggs, Cahill, Anderson, Puk, and Holmes.

There are still two names worth following in Nashville:

Naile: 4.05 ERA, 80 ip, 51 Ks, 19 BB, 7 HR, 4.71 FIP

Jackson: 5.40 ERA, 10 ip, 11 Ks, 7 BB, 1 HR, 5.29 FIP

Sleeper prospect James Naile has been inconsistent, as his last 10 starts have included five sparkling quality outings and five outright disasters. It’s the same story for veteran Edwin Jackson, who was picked up off the emergency scrap heap and has put up one quality start and one disaster. Jackson can opt out on Wednesday if he so chooses.

Laureano gaining steam

The Sounds lineup has lost some star power as well, with outfielder Dustin Fowler finding a permanent role in Oakland and infielder Franklin Barreto up for another stint in the bigs. However, a new name is emerging from the rubble.

Outfielder Ramon Laureano made our CPL last winter but then missed the beginning of the season with a broken finger. Now he’s back, and he’s off to an encouraging start in his first 105 plate appearances:

Laureano: .286/.371/.440, 115 wRC+, 3 HR, 12.4% BB, 23.8% Ks, 5-of-6 SB

After a 2017 slump with Houston’s Double-A club, he’s showing all the improvements you’d hope to see in his bounce-back. He’s hitting liners instead of popups, his batted balls are falling for hits, he’s drawing walks again, and he’s maintaining his midlevel power and plus speed. He’s playing RF, where his reputation as a plus defender with a good arm has never really been in question.

There’s another important consideration beyond Laureano’s raw numbers: He’s already on the 40-man roster. With such a packed disabled list, the A’s don’t have a lot of spare bodies to call on when needed. With Matt Joyce on the DL and Jake Smolinski up in his place, they’re down to filler outfielder Nick Martini, third catcher Bruce Maxwell, not-ready-yet speedster Jorge Mateo, and Laureano. One of them may have to be DFA’d in the coming days/weeks for the imminent return of Boog Powell from the 60-day DL, unless some other move clears a spot for him.

At what point might Laureano become the next in line for a look in Oakland? The return of Powell will complicate his path, but they bat from opposite sides of the plate so they aren’t complete duplicates. The closer fit for Laureano’s skill set is the role currently occupied by Smolinski, as a righty hitter who can play the corners and shift to CF in an emergency. There’s not necessarily a rush for Laureano to move up, as this is his first taste of Triple-A and he’s still got two more option years in 2019-20, but it’s time to at least begin including him in the conversation the next time a spot opens up on the big league squad.

Rest of lineup

The other prospects:

Boyd, OF: .275/.321/.361, 80 wRC+, 2 HR, 6.3% BB, 17.7% Ks

Mateo, SS: .222/.262/.362, 56 wRC+, 3 HR, 5.0% BB, 29.7% Ks

Neuse, 3B: .207/.259/.260, 36 wRC+, 0 HR, 6.9% BB, 37.1% Ks

Some signs of life lately from B.J. Boyd, who is hot since May 30 thanks to the return of his characteristically high BABIP (last 16 games: 20-for-62, 115 wRC+). Even better, Jorge Mateo is finally making some noise, going 8-for-18 with some extra bases, a reduced strikeout rate, and a 218 wRC+ over his last five contests. Still nothing from Sheldon Neuse, though, who is yet to homer in 323 plate appearances in the upper minors dating back to last season.

And the depth:

Martini, OF: .312/.429/.436, 136 wRC+, 5 HR, 17.0% BB, 19.4% Ks

Garcia, OF: .260/.379/.481, 125 wRC+, 11 HR, 12.5% BB, 18.4% Ks

Maxwell, C: .160/.214/.240, 15 wRC+, 0 HR, 7.1% BB, 32.1% Ks

Since returning last weekend from his MLB stint, Nick Martini is 10-for-25 with two homers, a 228 wRC+, and a walk for every strikeout. Anthony Garcia is on an eight-game hitting streak that includes three dingers. On the downside, Bruce Maxwell is 4-for-25 with nine strikeouts since moving down to the minors.

Sunday’s games

Full slate of action.

Triple-A Nashville: 6:05 p.m., Raul Alcantara vs. Albuquerque

Double-A Midland: Won 8-1, Jesus Luzardo vs. Frisco

High-A Stockton: LIVE, Bullpen Game vs. Modesto

Single-A Beloit: Lost 8-5, Mitchell Jordan vs. Clinton

Low-A Vermont: Won 4-3, Abdiel Mendoza vs. Tri-City

The rotation crunch is rippling down throughout the system. Alcantara is pushed back into a starting role for now in Nashville, and Stockton is patching together a bullpen game after sending several arms up the ladder (most recently Parker Dunshee). Luzardo was alright in his start but only struck out one batter.

Link to box scores