One of the more unique stories that came out of the Washington Nationals’ victory over the Cincinnati Reds on Saturday was when the two players involved in the MLB’s first ever Tanner-for-Tanner trade faced off against their respective former teams.

Tanner Roark started the game for the Reds, while Tanner Rainey entered in the sixth inning and picked up the win. After the game, the right-hander was also clearly pleased about getting his first career win against his former team.

“It was definitely a special moment,” Rainey said after the game. “But at the end of the day, it’s still a game, just coming in and trying to compete and doing what I can to try to keep us where we were.”

Though the trade seemed questionable for the Nats at the time, they have seen plenty of flashes of promise from their new reliever in his brief big league time.

When they acquired Rainey, the Nationals knew they were getting a flamethrower with tantalizing stuff, but stuff that he hadn’t commanded effectively in the majors so far.

“From what I’ve seen of Tanner [Rainey], obviously his fastball is electric,” manager Dave Martinez said this spring of the right-hander. “For me, it’s just about consistency with him and getting him in the strike zone consistently.”

In 2018 with the Reds, he posted an ugly 24.43 ERA in seven innings, striking out seven but walking 12. As it usually does with live-armed relievers, everything plays off of the fastball. Unfortunately, Rainey wasn’t able to consistently pound the zone with it.

Albeit in a very limited sample, his fastball was only in the strike zone 38.5 percent of the time. That allowed hitters to get ahead in the count, keyhole the pitch, and do damage in favorable counts.

Below is a clip of Rainey last season with the Reds. Funnily enough, this was his fastest pitch of the season coming in at 100.1mph according to Statcast.

As you can see, even though his velocity is eye-popping, the ball tails away drastically towards the hitter. That’s because as he releases the ball, he flies off to his glove-side, limiting his control over where the ball goes given the lack of a stable base.

Looking back at other pitches from Rainey that were among his fastest, he fell off quite a lot which likely led to some of the command issues he saw with the Reds.

It’s difficult to pinpoint what the exact issue was, but it appears as though Rainey was seemingly gunning for as much velocity as possible, trying to blow the ball past hitters. And when he was focusing on throwing as hard as possible, there was less focus on mechanics.

Last season, Rainey threw seven pitches that hit 100mph on the gun. However, this year, the highest he has reached is 99.2mph and he looks much more in control of his delivery.

“We went and reached for Tanner Rainey who’s shown that he has major league stuff and is kind of a reliable guy who can throw it over the plate,” Mike Rizzo told the Sports Junkies just after he was called up.

Below is the fastest pitch that Rainey has thrown this season that wasn’t swung at. It comes in at 98.9mph against the New York Mets in his Nats debut.

“He was really good. I liked what I saw. He had a nice clean inning,” Martinez said following the game. He loved Rainey so much that he went out and used him heavily the following night with a one-run lead in the eighth and a tie game in the ninth.

That extended second appearance is the only poor outing that Rainey has had with the Nationals.

Overall, he currently owns a 2.84 ERA in 6.1 innings to go along with a ridiculous 11 strikeouts, though he does have four walks in that time too.

But the underlying numbers behind those stats are arguably more impressive for the right-hander. Following Saturday’s game, Rainey had thrown 50 percent of his fastballs in the zone, up over 10 percent from last season.

With the velocity and spin to make the ball have a rising effect, he can generate swings and misses in the zone with ease. So far this season, he’s recorded a 15.1 percent swinging strike rate with his fastball, up almost 10 percent from last year.

His much-improved fastball command also allows his slider to flourish. Below is an example of his devastating off-speed pitch, making Carlos Gomez look foolish.

Now that hitters are more likely to expand their zone on the fastball with him pounding strikes, he can fool hitters with his slider that looks like a strike until late. Though technically classified as a slider, it has more of a sharp downward breaking action than other sliders.

Hitters are currently slashing just .125/.125/.250 against his slider while it’s also generating a 37.8 swinging strike percentage. Pretty good going from the right-hander.

“I’ve been able to use my slider, both to get into counts and put guys away, and that’s been beneficial for me,” Rainey told reporters after Saturday’s game.

“Obviously the fastball is not always exactly where I need it to be, but being able to get into the counts with the slider and also having that to put someone away with makes the fastball play a little better.”

In his inning and a third on Saturday, Rainey’s slider generated five swings and misses, including one that finished off a strikeout of Josh VanMeter. His manager was impressed.

“I think he had a little something, something there that first out after he got [Yaisel] Puig,” Martinez said. “He’s going to be a good one, he really is. I like what I see out of him. He’s hungry. He has that look, when he comes out of that bullpen that I really, really like.”

In a bullpen that is still lacking in reliable late-inning options, Rainey now appears to have found his way into the mix to try to get the ball to Sean Doolittle.

Kyle Barraclough previously appeared to be the top set-up option, but with his struggles, that baton appears to now be held by Wander Suero and Rainey, who got the set-up work Saturday against the Reds.

If Rainey can keep up the improved command he’s shown in his brief major league time this season, he has a real chance to be a lockdown eighth-inning man for the Nats. With a sky-high ceiling, we could be watching a closer-of-the-future flourish right in front of our eyes.