Why the Diamondbacks might not be ready to contend in 2023

With the season approaching, the Diamondbacks carry an undeniable air of optimism. They’re young, talented, fast and exciting. The overall mood at Chase Field is better than it’s been in years after a 22-win leap to 74-88 last season.

But external projections still suggest caution is warranted. According to DraftKings, they’re still +550 to make the playoffs. Fangraphs has them projected for a modest improvement, at 77-85. Even general manager Mike Hazen offered muted expectations, saying a successful season would be playing meaningful games in September.

This is how they could fall short of that ambition. If you’re more interested in the glass-half-full outlook, look here.

Diamondbacks face rotation question marks

On Opening Day, the Diamondbacks will start Zac Gallen, a veritable ace and one of the 15 best pitchers in baseball. It might seem weird, then, to begin with the Diamondbacks’ rotation.

But after Gallen, the rest of the rotation will need to punch above their weight. Merrill Kelly, the No. 2 starter, is more of a third starter. Zach Davies, the No. 3 starter, is more of a fourth starter. Madison Bumgarner, the No. 4 starter, is more of a fifth starter.

That’s not to discredit the Diamondbacks’ pitchers. But compare them to starters on teams widely expected to compete for National League Wild Card spots.

The Brewers’ No. 2 starter, Brandon Woodruff, finished fifth in NL Cy Young voting in 2021 and has a 2.84 ERA over the past three years. The Phillies’ No. 2 starter, Zack Wheeler, finished second in NL Cy Young voting in 2021 and has a 2.82 ERA over the past three years.

Kelly is solid, with a 3.37 ERA last year, but his predictive metrics based on strikeout and walk rates suggest that his ERA should be closer to 4.00 this year. For contenders, that uncertainty is the domain of No. 3 starters, like the Brewers’ Eric Lauer and the Phillies’ Taijuan Walker.

Instead, the Diamondbacks’ No. 3 starter is Davies. Throughout his career, Davies has overperformed his expected numbers, like he did last year, when he posted a 4.09 ERA against an xERA (expected ERA based on batted-ball data) of 4.56. Maybe that’s replicable. More likely, a strikeout rate in the 18th percentile and a walk rate in the 27th percentile will hurt Davies in 2023 unless he can find a way to improve upon them.

And then there’s Bumgarner, who labored to a 4.88 ERA in 2022 with some of the worst underlying metrics in baseball. Players like that version of Bumgarner seldom have a place in the rotation on contending teams.

Maybe the Diamondbacks’ trio of promising young starters — Drey Jameson, Ryne Nelson and Brandon Pfaadt — will accelerate their development and change the fortunes of the club’s rotation. But that’s a heavy burden for three pitchers with seven major league starts between them.

Who are the Diamondbacks' impact bats?

Offensively, the Diamondbacks don’t have a glaring hole in the lineup. They also don’t have any stand-out stars.

Last year, Christian Walker was the team’s best hitter with a wRC+ of 122. wRC+ is an all-encompassing offensive stat that compares players to league average. Walker’s number means he was 22% better than average, good for 50th among qualified hitters. Every playoff team had one qualified hitter with a wRC+ of 128 or better. The average playoff team had a whopping 3.4 players who hit better than Walker.

Walker is an excellent player who hits the ball hard, draws a lot of walks, slugged 36 home runs and plays elite defense. But good teams have lots of Christian Walkers and a handful of guys even better than him.

Where does that come from for the Diamondbacks?

Ketel Marte has been that guy before, with a wRC+ of 150 in 2019 and 140 in 2021. He needs to get back to that level. Corbin Carroll was at 130 in his 32-game cameo. He needs to translate that into a full season. Maybe Jake McCarthy can build on his 2022 breakout, when he posted a 116 wRC+, even if his batted ball data suggests he was actually a below-average hitter. Alek Thomas and Gabriel Moreno have prospect profiles that indicate big years are possible.

In other words, it’s not impossible that the Diamondbacks could have a couple of legitimate, middle-of-the-order bats to pair with a deep lineup of above-average hitters. But a lot would have to go right to make that a reality.

The leap to the majors is hard for some prospects

One commonality in the names listed above: Most are young players with minimal major league experience. Combined, Carroll, McCarthy, Thomas and Moreno have played in 293 MLB games. That’s a lot riding on players who are relatively unproven at the major league level.

It’s one thing to succeed in 100 at-bats, as Carroll and Moreno did last year. But teams quickly learn to attack young hitters, making it difficult to sustain that success. Just look at Thomas. In his first 41 games, he slashed .275/.338/.451. From the 71 games between then and the end of the season, he slashed .205/.236/.280.

Thomas isn’t alone. When Marte reached the majors in 2015, he posted an impressive .753 OPS in 57 games. Playing a full season the next year, that number dropped to .610. The players who excel when they debut and don’t stop excelling are rare breeds.

As Orioles general manager Mike Elias told The Republic last year, “Learning to be a hitter in the big leagues requires hitting in the big leagues at some point.”

For the Diamondbacks’ brightest young talents, that learning curve could strike this summer.

Diamondbacks bullpen still unproven

The Diamondbacks' bullpen will be better than it was a year ago. The alternative is nearly impossible given the season they had in 2022.

But will it be good? Or even average? That’s a tougher question.

Over the past decade, baseball’s relentless pursuit of velocity has manifested itself in bullpens full of pitchers who throw 100 mph with wipeout sliders. The Diamondbacks added two intriguing arms in that vein — Miguel Castro in free agency and Carlos Vargas via trade. But Castro has a career 4.12 ERA and Vargas has yet to debut. Luis Frias is another power arm who will likely begin the year in the minors while Justin Martinez has already been optioned to Triple-A.

That leaves a slew of finesse arms to comprise the bullpen. The league’s best bullpens now average over 10 strikeouts per nine innings as a unit. The Diamondbacks only have two options — Andrew Chafin and Cole Sulser — who topped that mark individually last season. Chafin, Sulser, Joe Mantiply and Kevin Ginkel were the only options with a sub-4.00 xFIP (the most predictive commonly-used metric of future ERA).

One important caveat: None of the above includes Scott McGough, who excelled in Japan's top league, Nippon Professional Baseball, over the past four years and is likely to earn a back-end role.

Injury luck seems to be against Diamondbacks already

After being one of the sport’s most injury-stricken teams in their disastrous 2021 season, the Diamondbacks mostly avoided major injuries last year.

Baseball Prospectus calculates the percentage of projected WARP (their version of WAR) missed based on days spent on the injured list. By that metric, the Diamondbacks were the second-luckiest team in baseball, despite Nick Ahmed being limited to 17 games.

A reasonable expectation this season would be for the Diamondbacks to be twice as afflicted by injuries. Already, they’ve lost starting catcher Carson Kelly to a broken forearm with an unknown timetable and relievers Mark Melancon and Corbin Martin to injuries that are expected to sideline them for “months not weeks,” according to manager Torey Lovullo. For a team on the fringes of contention, a string of untimely injuries can make all the difference.

This article originally appeared on Arizona Republic: Bullpen, lack of power key reasons why Diamondbacks might not contend