Lucas Gilbreath’s career arc is uncommon in the context of league history. But his pandemic-afflicted climb up the Rockies’ organizational ladder is comparable to several rookies these days.

Prior to the Minor League shutdown in 2020, Gilbreath was a starter in High-A. But this year, he emerged as a reliever, debuting with Colorado on May 1. The early returns were shaky: He posted an 8.64 ERA in nine appearances that first month, heading back and forth from the Minors four times.

But Gilbreath was recalled for good during the first week of June, and the results quickly improved. By July, he performed even better. Now, his ERA is down to 4.09 and his past 11 relief outings have been scoreless, including a 1-2-3 seventh inning in Wednesday's 7-4 loss to the Giants in the series finale.

“There’s a comfort factor and now a confidence factor bleeding into his game,” Rockies manager Bud Black said Monday night after Gilbreath’s clean effort in the series opener. “The shift to the bullpen, I think, was a good move by our player-development staff. He’s got talent. He’s got a good arm. He’s got a Major League-quality fastball, he’s got a Major League-quality breaking ball. He just needs repetitions.”

The repetitions have been particularly steady since July, a span in which Gilbreath has a 1.83 ERA and 9.6 strikeouts per nine innings over 19 outings. Black praised the 25-year-old’s growing understanding of “what it takes to be a big leaguer,” as well as his ability to throw strikes. But not all strikes are created equal, and maybe that’s the key to Gilbreath’s success.

Gilbreath is a two-pitch lefty: He has a low- to mid-90s fastball and a slider with some above-average drop. In that messy month of May, both pitches garnered chase rates below 20 percent, according to Statcast. In other words, he wasn’t fooling anybody.

And at that time, his fastball was thrown predominantly in the zone (56.9 percent), while his slider was not (42.1 percent). In recent months, he has practically flipped those rates.

Gilbreath’s in-zone percentage on sliders, since July, is now 56.9 percent (i.e. exactly what the fastball’s rate had been in the early going). His fastball, meanwhile, has been thrown in the zone just 47.2 percent of the time in that same span.

Gilbreath’s chase rates are still pretty low (combined 24.2 percent since July), but that’s OK. Being able to throw his slider for strikes means he doesn’t have to rely as much on hitters swinging at out-of-zone pitches.

Take Monday, for example. With one on and one out in the ninth inning, Gilbreath threw a pair of in-zone sliders (called strikes) to Steven Duggar before coaxing a groundout on a fastball. Then Gilbreath struck out Tommy La Stella on a fastball over the plate after working in with his slider on the two previous pitches.

That’s the type of stuff Black notices in his pitcher, and it’s why Gilbreath has been able to make the jump from A-ball to the Majors in two years.

“Doesn’t happen often, but we believed in the guy,” Black said. “And we believed in the arm.”