PHOENIX -- For all the talk about sustainability and spending with this Padres roster, the biggest key to long-term success will be the team’s ability to replenish its once-top farm system. General manager A.J. Preller said as much earlier this month.

"We relish the opportunity," Preller said. "You’ve got to go out, and you’ve got to scout and every single year, have good drafts, have good international programs. But also, we feel like there’s still a lot of talent in the system."

• Padres' Top 30 Prospects list

In the wake of a summer in which the Padres dealt droves of prospects to acquire Juan Soto and Josh Hader, the upper ranks of the system have, understandably, thinned. But Preller wasn't wrong about the talent in that system.

Case in point: the hot start for Single-A Lake Elsinore, which entered play Sunday in first place in the California League, with the league's best run differential at +29. The Elsinore pitching staff has led the way with a league-best 3.08 ERA.

An early standout on that staff is left-hander Robby Snelling, ranked by MLB Pipeline as the Padres' No. 5 prospect. Playing his first season of professional ball, he has opened the year by posting a 0.82 ERA across three starts, with 14 strikeouts and just four walks.

The 39th overall selection in the 2022 MLB Draft, Snelling is precisely the type of player the Padres need to hit on to revamp their farm system. Team evaluators were high on Snelling last summer – high enough to give him a $3 million signing bonus to lure him away from a potential two-sport baseball/football track in college.

But Snelling didn’t pitch at any level of the Padres’ system last summer, as the team focused on reworking his build in Peoria, while adding a changeup to his already excellent fastball/curveball combo. Hard to argue with the early results.

Here's an early season rundown on each level of the Padres' system:

Triple-A El Paso 
Some prospect named Fernando Tatis Jr. leads the way with seven homers, 15 RBIs and a .515 batting average. (Oh, right. We're hearing Tatis has since arrived in the big leagues.)

Beyond Tatis, Tim Lopes is building on his strong spring, hitting .342 with a 1.011 OPS through 19 games. Brandon Dixon, despite being shuttled between Triple-A and the Majors, has done nothing but hit for El Paso. The Chihuahuas got off to a 7-13 start.

Double-A San Antonio
It has been a rough go offensively for the Missions, who entered Sunday without a qualifying hitter posting an OPS above .650. Tirso Ornelas, once a big-name prospect and now ranked No. 28, has scuffled a bit to start the season, but he has shown promising signs, as well. Ornelas has a pair of homers and 10 walks through 14 games, though he's hitting just .188. The Missions have won three straight and sit 7-7 in the Texas League.

High-A Fort Wayne 
Jackson Merrill, the Padres’ top prospect, appeared on the verge of a breakout, having crushed a laser home run on Tuesday. But he missed a few games while dealing with a stomach bug.

On the pitching side of things, keep an eye on 21-year-old right-hander Jairo Iriarte, who punched out 17 in his first 10 innings. "Big-time stuff," one evaluator said of the No. 11 prospect.

Single-A Lake Elsinore 
There are a number of standouts to mention, in addition to Snelling. Fellow starting pitchers Manuel Castro, Austin Krob and Isaiah Lowe (the Padres' No. 25 prospect) have made two starts apiece, none with an ERA above 2.25. Offensively, catcher Anthony Vilar posted a 1.318 OPS through his first 10 games.