BALTIMORE -- At this time last year, Dylan Bundy watched the first few innings of games beyond the left-center-field fence in the bottom tier of the double-decker bullpen at Camden Yards.
Bundy had a 3.08 ERA in his 38 innings coming out of the bullpen when the Orioles made the decision to transition the righty to a starter on July 17. In the starting role, Bundy threw 71 2/3 innings with a 4.52 ERA in 2016. So far this season, Bundy has thrown 76 2/3 innings, posting a 2.93 ERA.
So how does a pitcher become so much more dominant on the mound in just eight short months?
"Just learning how to pitch, and also facing these guys in the AL East last year," Bundy said. "I got to learn a little bit about them and this year carried it over, but then the other thing would be adding the slider."

The slider has been the difference-maker in Bundy's performance. Last year, he relied heavily on his four-seam fastball, using it 61 percent of the time, according to Statcast™.
This year, according to Statcast™, Bundy's dependency on the four-seamer has dropped to 48 percent, with the slider being thrown 21 percent of the time. Although 21 percent may not seem like a lot, his slider has been very effective all season.
Bundy has held hitters to a mere .180 batting average on his slider (11-for-61), according to Statcast™. When batters do make contact with his pitch, the average exit velocity of 82.3 mph is the ninth lowest among starting pitchers with over 25 batted balls allowed on sliders.
"It's been a good pitch for me, and our catchers, they have the trust in it that I can throw it behind in the count -- 2-0 or 2-1 -- to get a swing and a miss," Bundy said. "That's been a good pitch. Hopefully I can continue to develop it."

A swing and a miss on Bundy's slider has happened 43 percent of the time, which is the 15th-highest whiff rate of almost 150 pitchers with at least 50 swings against their slider, according to Statcast™. He has been commanding this pitch to two specific areas: the low-outside corner of the strike zone to a right-handed hitter, and just off the plate low and away to get right-handed hitters to chase.

Statcast™ shows that in the low-and-away region of the strike zone, Bundy has gotten swings-and-misses on 41 of the 120 sliders he's thrown, which is the third-highest swinging strike percentage of pitchers who have thrown at least 100 sliders in that spot.
Last season, Bundy only made it through six innings in three of his 14 starts, while in 2017, the righty has had 10 quality starts in just 12 outings.
"We kind of protected him a little more, and I think he's just growing as a pitcher," O's manager Buck Showalter said. "It's just continuing maturing of a young pitcher. He's a pretty wise pitcher. You can tell he knows where his outs are and who he may not feel confident with the matchup. He's just very mature, pitching-wise, beyond his years."
With an Orioles team whose starters have been inconsistent for the majority of the season, the combination of Bundy's maturation and the effectiveness of his slider has turned him into the surprising rock of the starting rotation. If the slider continues to develop, the righty could become a dangerous weapon.