When we first came up with this series idea, the Mariners hadn’t yet stomped the Angels in a three-game sweep, Garrett Richards wasn’t on the DL, and I had recently published this piece about how the Angels and Mariners were set up to enjoy a good old-fashioned rivalry last seen in PST when the Seahawks went toe-to-toe with the 49ers. With Houston’s core of young, controllable talent and world-beating pitching, it seemed like the Mariners and the Angels, owners of the Best Player in Baseball and the Generational Talent Two-Way Player, were set up to battle for second place for a while in the division. Back on June 11, when I published that article, Seattle sat at just over 60% odds to make the playoffs on Fangraphs, with the Angels at 26.4%. In the AL West, Oakland was hanging out at just about 7%, right around where the Twins were. I reminded myself to write up the Angels’ Threat Assessment, and then promptly forgot as the Mariners went on to play thrilling baseball all through June.

Flash forward to the All-Star Break, and things suddenly look very different. Cleveland, Boston, Houston, and New York are still overwhelming favorites to make the postseason. However, the Mariners, owners of 88% playoff odds on July 3, have tumbled to 65.7%. Meanwhile, the surging Oakland Athletics, whose odds were just 8.7% on July 3, have surged to almost 30% probability of making the playoffs, while the Angels have cratered to beneath 3%. The A’s will enter the second half just three games back of the Mariners, and many fans are understandably feeling some panic. Enter the Threat Assessment.

Firstly, a huge amount of the A’s surge belongs to one player: third baseman Matt Chapman. In his second year in MLB, Chapman is showing no signs of a sophomore slump, posting 3.5 fWAR over the first half alone despite being sidelined by a hand injury for a time, thanks to his platinum-level defense, double-digit home runs, and superior plate discipline. Continuing the youth movement, 26-year-old Chad Pinder looks to be a late bloomer, carrying a wRC+ of 120 in his third professional season, the first where he’s accrued more than 200 plate appearances before the All-Star Break. 24-year-old Matt Olson, the man who made Ryon Healy expendable, is currently leading his former counterpart with a 113 wRC+ vs. Ryon’s 96, and just edged our favorite frat boy in HRs, 19 to 18. Really, the only significant difference between the two is Olson appears to understand how to take a walk (LEARN TO TAKE A WALK, RYON).

Old-timers are contributing in surprising ways, as well. Khris Davis is still Khrush Davis, and although he’s a liability in the field, he’s settled in well in a DH spot as a moderate income man’s Nelson Cruz. Journeyman infielder 34-year-old Jed Lowrie has 16 home runs before the All-Star Break—more than he has hit over a full professional season—on the highest BABIP he’s enjoyed since his freshman year in MLB. Marcus Semien, owner of a -5 DEF rating from Fangraphs in 2015, has a 9.8 (!) for his defense this year, offsetting what would be a career-worst wRC+ for his offensive contributions. Even anthropomorphic thumb/balaclava enthusiast Mark Canha has a surprising 1.7 fWAR with a 120 wRC+. And Stephen Piscotty, traded to the A’s in a goodwill gesture from the Cardinals so he could spend the final year of his mother’s life closer to her, has been an above-average batter despite being a below-average defender in the outfield.

However, there are weak spots. Matt Joyce hasn’t been very good (88 wRC+), but has collected over 200 PAs because he’s been less bad than fellow outfielder Dustin Fowler, the top prospect acquired in the deal that sent Sonny Gray to the Yankees, still working his way back from a brutal knee injury, and still-injured ex-Mariner Boog Powell. And Jonathan Lucroy continues to fill space for the A’s bright young catching core of prospects in Sean Murphy and Collin Theroux with a not-nice 69 wRC+ along with some...questionable defense.

Summing up the A’s position players, there are some solid numbers, but with a lot of streakiness built in. Here are some player’s rolling wRC+ numbers, month-to-month:

Marcus Semien: 105, 84, 59, 107

Stephen Piscotty: 104, 36, 149, 193

Chad Pinder: 172, 78, 87, 214

Mark Canha: 161, 58, 130, 156

Dustin Fowler: 52, 109, 73

Matt Chapman: 145, 67, 195, 91

The most consistent A’s players have been, on the higher end, Khris Davis and Matt Olson, and on the lower end, Matt Joyce and Jonathan Lucroy. In between them, however, it’s been a ride, with a lot of players catching fire in late June/early July, propelling the team into a strong finish at the All-Star Break. Meanwhile, the beat-up Mariners sagged and drooped, limping their way into two straight series losses to finish the first half.

In a way that will feel eerily familiar for Mariners fans, the Athletics offense has been carrying the water for a pitching staff besieged by injury. Aside from 123 innings from ace Sean Manaea, whose 3.42 ERA is significantly better than his 4.47 FIP, the A’s have enjoyed 52 near career-best innings from soft-tossing journeyman Trevor Cahill, 32 solid innings from tall journeyman Chris Bassitt, and 90 innings from the wonderfully mustachioed Daniel Mengden, who has an FIP approaching 5. Much like the 2017 Mariners, the A’s have been busily opting pitchers up and down among the big-league club and Triple-A for the majority of the season to try to patch together a rotation. The numbers may look appealing, but the longevity of the pitching rotation is a question: only Manaea has crossed the 100-innings threshold at this point in the season, with the next-highest number belonging to Mengden, and the next-highest number belonging to reliever Yusmeiro Petit. For contrast, no Mariner rotation member has thrown fewer than 89 innings at this point in the season (love you, Wade).

As Petit’s heavy innings workload might indicate, the A’s pitching has been propped up by Manaea and the bullpen. Fun fact: four of the five AL West teams rank in the top ten in baseball for reliever fWAR, with the A’s just sneaking in at 10. (The Angels are 26th.) Oakland’s relief corps is led by All-Star closer Blake Treinen, breaking out in a way he never could in Washington, which might have something to do with his 3.2% HR/FB rate, which is 1/5th the number he posted in Nats Park in 2016. Rookie Lou Trivino has been the team’s best setup man, edging former Mariner Emilio Pagan out of that spot, and journeyman lefty Ryan Buchter is on pace for a career-best season. The aforementioned Petit has been a durable rock propping up a fragile rotation.

Bullpens are volatile, but Treinen looks like one of the best closers in baseball, so the A’s, like the Mariners, focus on getting the game to Treinen. This has led some, like Zach Kram at the Ringer, to remark upon the similarity in construction between the two teams: no black holes, role-players rather than stars, upgrade the defense from awful to decent. The difference is Oakland, thanks to their crop of tater-mashers (6th in all of baseball in HRs), enjoys a slightly better run differential...when those tater-mashers are mashing taters and not striking out (the A’s are in the top half of baseball in K%). The A’s lead all of baseball in hard-hit rate: much to the delight of Hitting Twitter, they are eschewing small ball and swinging to do damage. That’s very different from Seattle’s speed-and-contact-focused strategy. The A’s have the second-highest flyball rate in baseball, trailing the Twins by the barest margin, but their HR/FB rate is almost identical to the Mariners, right around the middle of the pack. Meanwhile, the Mariners put the ball on the ground much more often, and rely on speed to beat out throws and stretch singles into doubles. They’re also much more prone to swiping an extra bag than the A’s, who rank dead last in baseball for stolen bases.

As Dipoto has said, the 2018 Mariners are built like a vintage 1970s NL team. The A’s, on the other hand, seem to have sprung directly from the head of Hitting Twitter, to #ElevateAndCelebrate. Despite their outward similarities and surprising surges into playoff contention, the two teams are using different blueprints to put runs on the board. It will remain to be seen which strategy can propel a team through a strong second half and into a possible playoff berth.