Duane Underwood Jr.'s season hit a snag before he could even record an out.

Seven pitches into the season, Underwood was on the injured list. He missed a month and change. But since returning, Underwood has added another layer to Pittsburgh's bullpen.

Underwood is quietly putting together the best season of his career. Across 15 2/3 innings, Underwood has a 2.87 ERA and 2.12 FIP. For comparison’s sake, Underwood had a 4.62 ERA and 4.46 FIP in his first four seasons.

According to manager Derek Shelton, that success has partly been a product of mindset.

“What we’ve seen is he’s stayed in attack mode and trusted his stuff,” Shelton said. “He’s really done a nice job staying with that, ‘I’m going to attack people’ mindset. 'I’m going to go right after ever hitter.’”

Underwood added: “It was something halfway through the season last year that I just wanted to make a conscious effort to do. I think very highly of the stuff I have in my arsenal. Their message to me was, ‘You can throw this stuff in the zone and still get swings and misses. After I started to repeat and do those things, it gave me more confidence.”

The pitch that's especially played for Underwood -- one that he’s been throwing far more frequently -- is the sinker. Across 19 plate appearances, opponents have a .188 batting average and .188 slugging percentage against Underwood’s sinker. With a Run Value of –2, the sinker has been the right-hander's best pitch thus far.

Early in his career, Underwood seldom threw the sinker. From 2018-20, the sinker only accounted for 4.3 percent of all pitches he threw. In '21, Underwood bumped up his sinker usage to 10.1 percent. This season, he’s gone to the sinker for 23.5 percent of all pitches, just a tick below the changeup that he throws 23.9 percent of the time.

Interestingly enough, Underwood’s sinker wasn’t all that effective last season. Across 40 plate appearances, opponents had a .429 batting average and .771 slugging percentage. This season, though, there's been an uptick in sinker quantity and quality, which may have to do with pure velocity. In 2021, Underwood’s average sinker was 93.3 mph. This season, an average sinker clocks in at 95.6 mph.

“The [velocity] for it is up and it has true movement,” Underwood said. “It’s not something that I have to really force.”

Along with emphasizing the sinker, Underwood has added a new pitch to his repertoire as well.

In his first three seasons, Underwood didn’t throw a single cutter. Last season, he threw the pitch 10 times, but the cutter still didn’t even make up one percent of all pitches he threw. This season, the cutter usage has skyrocketed to 16.5 percent of all pitches. Underwood said the team liked the pitch’s profile, and he’s used the games as an opportunity to give the pitch some fine tuning. As things stand, Underwood has the billing of a five-pitch pitcher.

“It’s gotten better pretty much every time out,” Underwood said. “Just finding consistency with it, finding where I want to throw it, finding spots to throw it in is all very important.”

With the cutter and sinker in tow, Underwood is generating a fair amount of of the very soft contact. So far, Underwood has an average exit velocity of 85.0 mph. His career average exit velocity, by comparison, was 89.4 mph. If Underwood had enough innings to qualify, he would have the 20th-best mark in the league, which would roughly be the 95th percentile.

That success has, in turn, resulted in manager Shelton turning to Underwood in more high leverage situations. “gmLI” is a stat that measures the average “leverage index” of when a pitcher enters a game. The higher the number, the more pressure the situation. With this stat, 1 is average. Entering this season, Underwood’s gmLI was 0.65. This season, by comparison, his gmLI is 1.15. In short, Underwood is appearing more often when the heat is on.

“I believe in our whole staff,” Underwood said. “I think we got a great group of guys. There’s a lot of guys that have a lot of talent down there in the bullpen. “