The Dodgers have not gotten off to the start they would have liked this season. Failing to win even half their games, they’ve seen the Diamondbacks parlay a strong first month into a place atop the NL West standings. The combination of those two developments has allowed the D-backs to turn the Dodgers’ projected 14-game divisional edge at the beginning of the season into a complete tossup.

Injury has played a part in LA’s struggles. The club, of course, recently learned that star shortstop Corey Seager would miss the entire season with Tommy John surgery. In addition to Seager, Logan Forsythe, Yasiel Puig, and Justin Turner have all missed time, as well. Despite all that, however, Dodgers position players rank third among NL teams in WAR. The Dodgers’ depth in the lineup has thus far passed the test.

For much of the the season’s first month, the club’s rotational depth hasn’t been tested in the same way. It’s about to be, however. And a good season out of prospect Walker Buehler — once a luxury in the organizational depth chart — could be necessary for the team to overtake the Diamondbacks in the division.

Before the season started, the Dodgers opted to get under the competitive balance tax to save money. In doing so, they absorbed the contract of the thus-far resurgent Matt Kemp, sending Scott Kazmir and Brandon McCarthy to Atlanta. Kazmir, since released by the Braves, was purely a salary dump, but McCarthy represented some depth for a Dodgers’ rotation that already had quite a few arms. Walker Buehler was foremost among that depth, but after pitching around 100 innings last year in his return from Tommy John surgery, he might have to blow past that mark this year to keep the Dodgers in the race.

Back in February, Jay Jaffe addressed the Dodgers rotation and went through some concerns for each of the five Dodgers’ starters. In part:

Clayton Kershaw – “Long story short, the forecast for 192 innings might be on the high side of expectations, though they’re balanced by comparatively modest projections for a 2.60 ERA and 2.68 FIP.”

Rich Hill – “Like Kershaw, what looks like an optimistic total of innings is mitigated by a more modest run-prevention forecast (3.55 ERA, 3.77 FIP), with the additional caveat that Hill is on the verge of turning 38 years old.”

Kenta Maeda – “[I]t’s fair to wonder whether they’re better served with Maeda in a setup role.”

Alex Wood – “Given his lack of durability — he hasn’t qualified for an ERA title since 2015 and has already suffered a minor tweak of his right ankle this spring — his workload projection appears light but not out of line, a step back from last year’s 152.1 innings.”

Hyun-Jin Ryu – “Limited to just one major-league start in 2015-16 due to labrum and elbow debridement surgeries, Ryu made a decent return to major-league action last year, though he did set career worsts for ERA (3.77), FIP (4.74), ground-ball rate (45.1%), K-BB% (13.1%), and so on.”

Kershaw might not be matching his peak performance, but he’s still quite good. Hill is set to come off the disabled list Sunday, but can’t be relied upon for innings. Alex Wood has pitched very well with a bizarrely low 46% left-on-base rate inflating his ERA, and injuries always a looming concern. While there was talk recently of moving Maeda to the bullpen with the potential emergence of Buehler and the return of Hill, that is off the table now because Hyun-Jin Ryu seems likely to miss likely to miss a lot of time with a groin injury.

In Jaffe’s piece, he mentioned Buehler, Wilmer Font, Brock Stewart, and Julio Urias as the club’s primary rotation depth. Buehler’s now in the rotation, Font’s now in Oakland, and Urias is still out for a few more months, leaving only Stewart as rotation depth at the present time. Buehler really needs to step up for the Dodgers and, through two starts, he’s delivered, striking out 11, walking four, and giving up two runs in 10 innings.

Buehler had a brief cameo in the bullpen last season, but he’s changed a little bit since then, and perhaps some since he was named the 27th-best prospect in baseball over the winter, when Eric Longenhagen and Kiley McDaniel wrote the following:

His three-pitch mix is unique for a starter but enough to justify continued development in a rotation, and the fallback option isn’t all that bad.

At the time, those three pitches were the fastball (his best pitch), a curve, and a slider. In his two starts this season, Walker has also used a sinker to get batters out. It’s not just Walker’s pitch mix that makes him unique, though: his four-seam fastball is unlike the sort thrown by most pitchers. He throws it in the upper 90s and can blow it by hitters, like he does here against Brandon Crawford.

That’s a fairly typical use of a four-seam fastball. What’s interesting about Buehler’s four-seamer is that, while he utilizes it as a primary pitch, he also appears to profile as a ground-ball pitcher. Guys like Jon Gray and Taijuan Walker pull it off, but they feature a low-spin four-seamer that’s more conducive to inducing grounders. Walker’s spin rate on his four-seamer is much closer to average. Luis Severino pulls off a similar feat, but mainly because hitters can’t get his slider in the air. Sonny Gray and Tyler Chatwood both pull the combo off, though Chatwood lacks command. Buehler’s four-seamer is faster than both of those pitchers’ offerings coming much closer to Severino’s heater. Introducing a high-90s sinker, which does have a grounder-inducing spin rate, should help remain a ground-ball pitcher even if hitters try to elevate the four-seamer. It’s a different offering that could give a different look lower in the zone.

While the fastball is great, it is perhaps best for setting up his slider and curve. Thus far, Buehler’s had more success with the slider this season, getting five strikeouts on that pitch, including this one of Brandon Belt.

The slider has a lot of downward movement, which renders it similar to the pitches thrown by Gray and Severino. Both of those pitchers have had success against both righties and lefties without too much of a platoon split. That downward movement should help Buehler to success against both righties and lefties, as well. Buehler’s curve is bigger and slower than his slider. He has yet to get a swing and miss on the pitch this season, but he’s gotten a handful of called strikes and every one put in play has been a ground ball. Even if the curve is just an occasional show-me pitch — and it could be more than that — and even if the sinker doesn’t completely develop, Buehler might be able to get by with using his fastball and slider for a vast majority of the time.

Luis Severino’s arsenal and success are hard to replicate. Buehler’s slider doesn’t have quite the same bite, but if you are going to hope for a high outcome for a still-developing pitcher, Buehler has some similar attributes to the Yankees’ ace. The curve and some development with the sinker could help the Dodgers’ rookie live up to his potential as early as this season. If the Dodgers want to defend their division crown, they are going to need a big season from Buehler, and he might be capable of delivering.