Colorado Rockies starter Jon Gray has been flagged as one of the best young, up-and-coming starters in baseball. At 6-foot-4 with an upper-90s fastball and a wipeout slider, it’s easy to see why Gray is considered one of the brightest young pitching stars in the game.

In his 50 MLB starts, Gray has flashed ace ability. Starts like his 16 strikeout performance against the San Diego Padres last September are proof he has the potential to be a No. 1 option in a rotation.

Many have been quick to declare Gray the ace and frontman of the Rockies rotation, but Rockies manager and former MLB pitcher Bud Black isn’t ready to do so just yet.

“I’m a tough judge on that for sure,” Black said when asked if he views Gray as a one or two within the rotation. “For me, a No. 1 has to pass the test of time. There are a number of factors that go into passing the test of time. It’s durability, that’s making 30-plus starts for a number of years and putting up numbers. Over 200 innings, quality starts, wins, stop losing streaks, all those things,”

Gray is good, yes, but Black is right in this instance. “The Gray Wolf” still needs to prove that he is a durable, reliable and dominant pitcher before the term ace and his name can be permanently linked.

Gray must establish a level of consistency on the mound if he’s going to make that happen.

He’s only thrown one complete game at the Major League level and has yet to pitch past the seventh inning this season. In his last seven starts, Gray’s outings have ranged between a two-inning, eight-earned-run debacle to a seven-inning, one-run gem.

In his 50th start, Wednesday against the Braves, he showed both sides of the argument for and against his ace potential.

He faced the minimum number of hitters through four innings, allowing just one hit, striking out five and inducing four ground-ball outs. In the fifth, he allowed a pair of hits and needed a diving catch from shortstop Trevor Story, spearing a line drive that would have scored a pair of runs, to end the inning. In the sixth, he walked a relief pitcher to lead off the inning. A pair of singles and a second walk in the inning later, he had surrendered two runs. He picked up a win to push his career record to the positive and lowered his ERA, but looked shaky the third time through the lineup.

In his career, Gray is now 15-14 with an ERA of 4.78. He’s logged 271.1 innings since getting called up which gives his starts an average length of 5.1 innings per outing.

While he’s improved those numbers this season, going 5-2 with a 4.74 ERA in 12 starts, nobody is classified as a number one with those numbers.

That said, Gray is just 25 years old, giving him plenty of time to establish himself as an ace.

Given his pitch repertoire, which now includes a traditional curveball and an improved changeup, it’s easy to see why many believe he has the makeup of a true No. 1.

Just because Black is not ready to crown Gray an ace just yet doesn’t mean he believes Gray can’t be one down the line. Black has liked what he’s seen from Gray since taking over as Rockies manager.

“Potentially, yes,” Black said of if he could see Gray evolving into a number one or two. “Everbody wants to anoint like right away. No, you have to pass the test of time.”