The D-backs are one of the hottest teams in baseball. Yes, the squad that went just 51-111 last season has now won 11 of their last 14 to improve to 17-14 on the season. As ludicrous as this sounds, the Snakes are tied for the final NL Wild Card spot, and their pace of 89 wins will be in playoff position come the season’s end. Last year witnessed the Giants, considered at the time to be only beginning their rebuild, catapult to 107 wins–the most in baseball. Could the D-backs make a similar journey to the postseason? To answer that question, we first must consider how authentic the D-backs’ hot start has been.

The club’s success has been built on the back of its starting pitching. As a group, their 2.34 ERA is the second best in baseball, and among the regulars, only Humberto Castellanos has an ERA above 4.00. Zac Gallen, Merrill Kelly, and Madison Bumgarner are all among MLB’s top-15 pitchers for the lowest ERA (min. 20 IP). Any team that starts games off allowing this few runs is going to win a lot of ball games regardless of how potent the offense is.

However, luck has favored the D-backs’ starters so far, but they likely won’t receive the same benefit going forward. Here is a table of each starter’s ERA, xFIP, and DRA. xFIP measures pitching performance on the same scale as ERA but based solely off of strikeouts, walks, and flyball rate. While it seems overly simplistic, it adequately removes luck from the equation to help us understand a pitcher’s true skill. Where xFIP lacks complexity, DRA makes up for it. It attempts to appropriately credit pitchers for every event on the field while throwing out the effects of park, umpire, quality of competition, weather, and more. (DRA is also on the RA/9 scale, so its values are slightly larger in general.)

Bumgarner’s row jumps out at you. How could a pitcher with one of the best ERAs in baseball be almost 40% below average in terms of DRA? Well, Mad Bum’s walk and strikeout rates have been at career worsts through the first month of the season, and he hasn’t transformed into an extreme groundball pitcher overnight. Pitchers who hand out walks and then allow a bevy of fly balls tend to get burned by home runs and extra base hits. When the ball is finding gloves, that won’t lead to a lot of runs, but that’s largely due to luck, rather than what Bumgarner actually has control over. Had a few balls gone a few feet further or been hit a bit to the right or left, his ERA would tell a very different story.

But there is good news in that paragraph if you squint hard enough. Since his strikeout and walk rates are at career worsts, it’s fairly safe to expect that they would improve going forward. Just because the season hasn’t gotten off to a great start for him doesn’t mean it will continue this poorly. In fact, his fastball velocity–a cause of concern over recent seasons–has risen to levels it hasn’t seen since the end of his time in San Francisco. Bumgarner is 32, and he won’t be a viable rotation candidate forever, but he may still have some worthwhile seasons left in him. Unfortunately, the level of run prevention that’s reasonable is not in line with what we’ve seen so far, and the team will have to pick up that production in other ways going forward.

For the remainder of the rotation, their raw run prevention likely won’t be matched for the rest of the season, but the advanced metrics aren’t particularly pessimistic either. Both Gallen and Kelly are among the league’s leaders in DRA. While the former will allow more walks and homers going forward, he’ll also likely strike more individuals out, and he could stay atop pitching leaderboards for much of the season. The latter’s strikeout and walk rates are in line with his career norms, and while he’ll also be burned by more homers going forward, he’s controlling the ball well enough to be a decent pitcher even with bad luck. With both pitchers potentially under control through 2025, the D-backs have the start of a contending rotation on hand.

Behind them, Davies and Castellanos are performing as well as one could expect. Davies was brought in on a one-year contract to fill the black hole at the end of the rotation. Thanks to a groundball rate over 50% for the first time since 2017, he’s been league average by DRAs standards. He’s done a better job of keeping his underwhelming pitches as far from the center of the plate as possible. With a low strikeout rate and a high walk rate, Davies will continue to live on the edge, but if he hangs in there, the D-backs may be able to get something for him at the trade deadline. Castellanos is in the rotation because the team has no one else, and he’s managed to survive. The 24-year-old’s best shot at finding a long-term home is in the bullpen.

While many of the individual cases are encouraging given the pre-season expectations, the overall outlook on the rotation isn’t rosy enough to expect the team to continue to thrive. At best, they have two front-end starters, two back-end rotation guys, and a replacement level pitcher. At worst, they have a two-man rotation with three question marks riding along. Yes, the offense is going to hit better than .201 for the rest of the season, but their improvement won’t make up for the rotation’s fall back to earth. At the start of the season, I predicted that the club would come away with 73 wins, which was in line with many projection systems. With their hot start, I would update that prediction to between 75 and 77 games, which is still a remarkable improvement from last season.

It is encouraging to see such strong starts from Gallen and Kelly. They are the pitchers this team needs if they want to compete in the coming seasons. With a wave of prospects itching to debut and a modest amount of money available to spend, competitive baseball could be returning to the desert sooner than expected. But maybe save your bets ‘til next year.