Jake Arrieta oozed potential. It came through his every pore. He was 25, talented, and part of what then-Baltimore Orioles manager Dave Tremblay referred to as his "cavalry," a group of young pitchers who would lead the franchise back into a state of perennial postseason contention after years as an irrelevant also-ran.

Arrieta was, basically, Nick Pivetta.

That was eight years ago. And although Arrieta went on to win a Cy Young Award and eventually a World Series, it didn't happen until after he left the Orioles. Were it not for a trade to the Chicago Cubs that freed him from the bad advice he had been getting from a pitching coach who didn't understand him and didn't care to, it's unclear even to the stone-faced righthander if his career would have launched.

It's little wonder, then, that Arrieta takes so seriously his role as a mentor to Pivetta and the other impressionable Phillies pitchers. Since he joined the team midway through spring training after signing a three-year, $75 million contract, Arrieta has considered it his responsibility as the Phils' highest-paid player to help his younger rotation mates avoid the pitfalls that once threatened to derail him.

"I've been victim to bad information at points in my career," Arrieta said in a long-ranging conversation last weekend, "and I don't want to see guys that are on my side go through that same thing."

But a funny thing has happened three weeks into the season. Arrieta is learning as much from Aaron Nola, Pivetta, and Vince Velasquez as he is teaching them.

The upstart Phillies have won 13 of 16 games. They are 9-1 at home and 14-7 overall, their best 21-game start since the 2011 club went 15-6 en route to 102 wins. And the starting rotation is the biggest reason for the fast start. While the Phils are batting only .230 as a team, the starters have combined for a 3.01 ERA, lowest in the National League through Sunday and fourth-lowest overall behind the Houston Astros (2.10), Boston Red Sox (2.43), and Cleveland Indians (2.66), all World Series contenders.

Nola has continued the roll on which he ended last season, posting a 2.30 ERA through five starts. Pivetta  has harnessed his previously erratic command and ridden a 28-4 strikeout-walk ratio to a 2.57 ERA in five starts. Velasquez, who will start Tuesday night's series opener against the Arizona Diamondbacks at Citizens Bank Park, has a 3.80 ERA. But a deeper dive into his numbers reveals the NL's fourth-best fielding-independent pitching (2.22), a metric that focuses solely on the outcomes a pitcher can most control (home runs, strikeouts, walks, and hit by pitches).

Arrieta says he didn't know much about the young Phillies starters until he joined them in spring training. But their dominance — the rotation has allowed three earned runs or fewer in 12 consecutive starts for the first time since 2011, when it consisted of Roy Halladay, Cliff Lee, Cole Hamels, and Roy Oswalt — has been energizing even to a pitcher as seasoned as Arrieta.

"It doesn't matter if it's veteran, rookie, guys with a couple years [in the big leagues]. It's always inspiring to see guys progress," said Arrieta, who struck out 10 Pittsburgh Pirates on Thursday night and has a 2.04 ERA in three starts. "I benefit from watching guys like that, very much so."

OK, let's pause here and add a necessary disclaimer: It's early. Very early. The season is not yet a month old. Surely, nobody around here needs to be reminded that the 2016 Phillies went 14-10 in April and still wound up losing 91 games. Or that last year's team was 11-9 before losing 26 of the next 32 games.

But there's tangible evidence that Nola is emerging as a top-of-the-rotation force. Pivetta and Velasquez have made obvious improvements, too. If those two starters, in particular, are able to maintain their consistency, they could make the difference in raising the Phillies' ceiling from the level of merely a fringe playoff contender.

"There's no other way that we get to the next step if they don't [progress]. That's not possible," Arrieta said. "And not to single those two out — if we want to play the last game of the season, which means the last game of the World Series, we all have to do that, not just Nick or not just Vinny — but if those guys both do [get better], it benefits our ballclub tremendously."

Said manager Gabe Kapler: "I think it's the emergence of Nick. I think it's the emergence of Velasquez. I think it's relievers we can go to that have behaved like the guys you depend on every day in the seventh, eighth, and ninth. It's very encouraging."

For now, though, Arrieta will continue to observe Pivetta's bullpen sessions, stressing the importance of trusting his electric fastball and bending curveball in the strike zone rather than trying to be too fine. And Arrieta will keep drawing inspiration from his younger teammates, too.

"Right now, there's an internal competition among all five of us that's completely necessary for us to have long-term success," he said. "Watching Nola throw eight strong innings, you follow that, you want to do the same thing — or better. Watching Nick out there, he's doing everything we're talking about when we work in our bullpens. We're all in this thing together, and to see the strides that guys are taking, it's very exciting."