As the A's added to their bullpen, with the acquisitions of Jeurys Familia and Shawn Kelley this late-summer trade season, they believe they are simply bolstering an already elite unit. All-Star closer Blake Treinen is in the midst of a career year, but it's flamethrowing right-hander Lou Trivino who has been the biggest surprise player for arguably the Majors' biggest surprise team. 

Trivino, who entered the year mostly unknown outside of Oakland as the club's No. 27 prospect, per MLB Pipeline, has posted the Majors' third-lowest ERA among relievers (1.16) and racked up 62 strikeouts in 54 1/3 innings -- numbers that should work him into consideration for the American League Rookie of the Year Award, particularly given that Trivino is being entrusted in high-leverage situations, mostly when the A's are tied or trailing.

"You spoon feed him early on, and the next thing you know, he's in the seventh, eighth inning and pitching in close games and a lot of tie games," Oakland manager Bob Melvin said. "He's around a lot of times because we come back for the win. There's a certain stress level that comes with the territory when you pitch those type of innings, but he's been up for the task. He's a tough kid. He likes to pitch."

Trivino is in his second stint with the big league club this year, and this one figures to last. After quietly putting together five productive Minor League seasons, the 11th-round Draft pick as a starter in 2013 wowed in Spring Training with his ability to throw with triple-digits velocity for strikes.

Trivino throws an elevated four-seamer, a sinker he moves in on righties and a wipeout cutter, the pitch that got him drafted. He also throws a curveball and a changeup, both plus pitches, but he hasn't used them much because his fastballs have been so effective.

"Usually you stick with your two main pitches that you know have a higher chance of working," Trivino said. "And it's trusting, not only what your catcher puts down in this count, but trusting that what you're doing works in the zone. There are some times where I try and get a lot of guys chasing out of the zone instead of attacking the zone. Sometimes you've just got to refocus, and my mindset is that I'm going to try and throw as many pitches in the zone as I can and attack the hitter within the zone. It's a mindset that's worked so far."

Throwing three variations of a fastball isn't novel, but not many who do so possess the velocity Trivino does. He's topped out at 100.4 mph on his four-seamer, his 97.7 mph sinker average trails only the Cardinals' Jordan Hicks (an unprecedented 100.2 mph). And among 111 pitchers who've thrown at least 50 cutters, Trivino's 92.7 mph average is MLB's fourth highest.

"It's not very normal," A's catcher Jonathan Lucroy said. "Obviously being able to throw a four-seamer, a good sinker and then a cutter off that -- especially with that kind of velo -- that's not something a lot of guys can do. That's why he's been so effective. It's because he can do that."

Lowest batting average allowed on cutters in 2018
Min. 10 at-bats decided on cutters (112 pitchers)

1. Adam Wainwright: .091

2) Lou Trivino: .100

3. Jace Fry: .103

4. Diego Castillo: .127

5. Randy Rosario: .128

Just three years ago, when Trivino was a starter for Class A Advanced Stockton, he says his fastball sat in the low 90s on a good day. Mike Connors, who Trivino enlisted at the Tri-State Elite Baseball Academy in Quakerstown, Pa., emphasized urgency and discipline to a revamped conditioning regimen that slowly led to an uptick of nearly 10 mph.

"For Lou, we just thought he was in a make-or-break year," Connors said, "so we thought he needed to gain velocity, because at the time he was maybe 88-91, maybe topped 92. So we just thought, 'All right, you're basically a dime a dozen, so we need to gain velocity.'"

The diagnosis revealed that Trivino wasn't creating enough hip/shoulder separation in his delivery. To the naked eye, when a pitcher has fluid hip/shoulder separation, his arm is still rearing as he begins to turn his hips and shift weight forward. As the hips open independently, strength is generated from the feet up, with the abdominal muscles contracting, which transfers more force through the core and to the arm -- all while putting less stress on the shoulder and elbow. Doing so also keeps the ball hidden marginally longer, creating more deception.

"You're engaging the big muscles," Oakland pitching coach Scott Emerson said. "Your back, your big muscles, which is your core, is the strength of your body, and when you can engage them and you can coil them and uncoil them, the arm is along for the ride."

"I've found how to throw," Trivino said. "Now I'm no longer thinking mechanics with delivery. Now it's just when I'm releasing the ball, trying to be behind the ball, on top of the ball, more just hand placement, not necessarily how my body moves."

Flexibility is a key component, which is why Trivino also ditched an undisciplined diet. Plyometrics, jumping and general weight lifting were key, but the most significant component for Trivino was his medicine ball. Trivino mimicked his delivery on the mound while unleashing a med ball into a wall, focusing on short burst movements with late explosiveness. Med ball workouts are particularly effective for high-velocity pitchers.

Much of Connors' instruction has admittedly been trial and error. But so far, it's worked. He and Trivino are already discussing plans for the offseason, with more emphasis on running. For now, though, their discussions largely center on how rewarding it's been to watch Trivino transform into a pitcher who is contributing in a playoff hunt. 

The A's entered Monday with a 2 1/2-game lead over the Mariners for the second AL Wild Card spot, and they quietly trailed the Astros by only four games for first place in the AL West. The additions of Familia, the former Mets closer, and Kelley, who had a 3.34 ERA with the Nats before being designated for assignment last week, have assembled an embarrassment of riches that has led to a 46-0 record when leading after seven innings, and Oakland is only MLB club undefeated in such games.

Trivino's role may change some -- he's been entering in the the seventh inning instead of the eighth more since Familia was acquired -- but Melvin suggested that Trivino will still be deployed in close, late games.

"The bullpen is ridiculous," Trivino said. "It's just something I'm very thankful to be in. I'm just blessed to be here, whether it's as a long reliever or closer or starter, I'm just happy to be able to contribute."