This Braves lefty has quietly become a bullpen ace

When Braves lefty Dylan Lee takes the mound, everything about him looks super-casual. His face seems expressionless. He appears emotionless. Even his delivery is unremarkable.

But then, there's usually not much glory in a setup role. You're almost never the star of the game. Nobody wears your jersey in the stands and nobody hunts your baseball card.

So, to the uninitiated, Lee's demeanor could come across as indifference. But to anyone paying attention, and especially to opposing hitters, his look might be better compared to The Terminator -- because the results are usually nasty and efficient.

So, if there were glory in being a setup guy, Lee would be among the most lauded pitchers in baseball. That's because Lee, despite not having an overpowering fastball (around 93 mph) or an especially noteworthy breaking pitch, has emerged as one of baseball's most effective lefty relievers. It's even safe to use the E-word -- because Lee has become elite.

Though he's among the best bullpen lefties in several key areas (we'll get to that in a bit), Lee has been the literal best in two critical areas over the past two-plus seasons.

Since the start of the 2024 season (135 appearances), no qualified lefty reliever has 1) caused batters to chase pitches out of the zone at a higher rate; and 2) caused a higher rate of overall whiffs than Lee.

His 34.7 percent chase rate during that time is the best among his lefty peers with at least 130 innings pitched. Meanwhile, his 35.6 percent whiff rate is easily the highest among that group. So, it makes sense that Lee also leads the group with a 5.00 strikeout-to-walk ratio during that span.

And it hasn't really mattered whether he's faced righties or lefties. While he's been effective against left-handed hitters (.235 average since '24), he's been even better against righties, holding them to a .201 average -- the fourth-best mark among lefty relievers over the past two-plus seasons.

What's interesting about all this is that nothing about Lee's arsenal stands out much in a league-wide context. His slider is his most effective pitch, with batters hitting .164 against it last season with a nearly 42 percent whiff rate. But its movement doesn't register

Now, consider the full picture.

Among all lefty relievers since start of 2024 (min. 130 IP):

Chase rate: 34.7% (best in MLB)
Whiff rate: 35.6% (best in MLB)
K/BB ratio: 5.00 (best in MLB)
Strikeout rate: 29.9% (second-best)
Percentage of batters retired: 73.9% (third-best)
Hard-hit rate: 33.4 percent (fourth-best)
WHIP: 1.02 (fourth-best)
Average exit velocity against: 86.3 mph (fifth-best)
Percentage of inherited runners stranded: 78.8% (fifth-best)
Overall opponents' average: .214 (sixth-best)

So, as you can see, when Lee pitches -- usually in the seventh or eighth inning to help bridge the gap to closer Raisel Iglesias -- it's good news for the Braves more often than not. And here's the proof: Since the start of 2024, Atlanta is 80-55 when Lee appears in a game. So far this season, he's appeared in nine games (eight innings) and has a 1.13 ERA. The Braves are 8-1 in those games.

It's not accurate to say Lee has been a secret weapon. Opposing teams are well aware of his skills. But more buzz is warranted -- among Braves fans and in the greater baseball world.

But then, a Terminator is most effective with a little anonymity.