More than two years after his departure from Boston, Jon Lester remains an obvious flashpoint in Red Sox decision-making. On Thursday, he added to his reputation as one of the finest postseason pitchers of this generation, snarling through seven dominant innings for the Cubs in which he allowed one run in seven innings while walking one and striking out six in Chicago’s 8-4 win over the Dodgers in Game 5 of the NLCS.

That performance represented anything but an isolated incident. Lester has now made 17 career postseason starts. His 2.42 ERA is sixth best among the 67 pitchers who have made at least 10 playoff starts, and second only to Curt Schilling (2.23) among the 21 pitchers who have made at least 15 career playoff starts.

Meanwhile, his dominance this October (0.86 ERA in three starts) follows a regular season in which he emerged as a Cy Young front-runner in the NL, going 19-5 with a 2.44 ERA.

The Sox’ inability to re-sign him remains a thorn, albeit one whose edges dulled this year with the emergence of Rick Porcello (acquired, in a roundabout way, for Lester) as a Cy Young contender in his own right. Even with Porcello, though, Lester’s performance has seemingly amplified the siren that has sounded around the Red Sox for most of this decade: Why haven’t they developed another Lester?

It’s a rich question, although it typically comes at the exclusion of another line of inquiry of comparable import: Can the Red Sox build a sustainable contender without developing another Lester?

The answer might seem obvious, but a look at the team for whom Lester now pitches makes it less so. Lester joined the Cubs as a free agent. So did John Lackey and Jason Hammel. Jake Arrieta was acquired in a trade. So was Kyle Hendricks.

The Cubs, in fact, had just one start all year from a pitcher who was drafted and developed in their organization — Sept. 29, when Rob Zastryzny logged 3⅔ innings in what was effectively a bullpen game.

If the Chicago roster assembled by president of baseball operations Theo Epstein wins the World Series, it would have the fewest homegrown starts by a World Series winner since . . . the 2004 Red Sox — assembled by GM Theo Epstein — got exactly one (a five-inning Abe Alvarez effort in the front end of a July doubleheader).

Those rotations represent outliers. On average, the 11 World Series winners between 2005 and 2015 received 67 starts from homegrown pitchers, meaning roughly two out of every five starts. That said, the 2004 Red Sox and 2016 Cubs — and, for that matter, a 2010 Giants team that received 118 homegrown starts — show that there’s no single template for constructing a championship-caliber rotation.

The Cubs’ roster-building efforts were purposeful. Chicago believed there was a scarcity of players who combined athleticism and power. Through the draft and trades, they built a roster filled with such players, while looking often to free agency for starting pitching — not just with Lester and Lackey, but with pitchers such as Scott Feldman (who netted the team Arrieta in a trade), Edwin Jackson, and Hammel.

Red Sox president of baseball operations Dave Dombrowski hasn’t been shy about building rotations with pitchers from outside the organization. His 1997 Marlins team won the World Series with a relatively modest 38 starts from homegrown starters (17 from Livan Hernandez, who was signed after defecting from Cuba). Dombrowski’s 2013 Tigers rotation, one of the most dominant in recent years in the American League, featured three pitchers acquired initially via trade (Max Scherzer, Doug Fister, and Anibal Sanchez).

“It’s happened many times,’’ Dombrowski said during the season of whether a team could be sustainably successful without a largely homegrown rotation. “You want to grow your own players of all sorts, including pitchers, but the reality is that when you start tracing throughout the years, there are very few rotations that are homegrown. A lot of times, you look at the Braves organization from way back when, [Greg] Maddux wasn’t a homegrown Brave, [John] Smoltz wasn’t a homegrown Brave. [Tom] Glavine was.

“I don’t mean that to take away from the importance of doing it. But I think it usually comes down to a combination of getting all kinds of talent.’’

The Red Sox do have a pair of standout pitching prospects in the lower minors.

“We’ve got a couple guys that really, with the addition of [first-round pick Jason Groome], have a chance to be stars at the top of the rotation,’’ said Dombrowski, who referred to righthander Michael Kopech as a pitcher with “a chance to be special.’’

“We have some guys that will pitch, and our bullpen depth is pretty good. But we can get better. We’re doing some things to try to get better. We’ve done a lot of things. But you don’t change everything overnight.’’

And so, until a pitcher like Kopech or Groome emerges, the Sox will require creativity in their rotation building — much as the Cubs did in identifying Arrieta and Hendricks as buy-low opportunities, much as Dombrowski’s Tigers did with Scherzer and Fister and more recently Michael Fulmer, much as the Red Sox tried to do this summer in trading for Drew Pomeranz.

The trade for Pomeranz, Dombrowski noted, was “very similar’’ to the deals he struck for starters in Detroit.

“He had ability, continued to make steps forward, looked like he was putting it together. People still weren’t completely probably all over him. You still heard that some people weren’t quite sold on him because he hadn’t done it for a consistent number of years,’’ said Dombrowski.

“But the reality is that if you have guys who have done it like that consistently for a number of years, they’re usually not available. That’s why there are gambles on those things. It’s not like you’re trading for Pedro [Martinez] in his prime, winning 20 games three years in a row and he’s 27 or 28 years old. Those guys don’t become available too often.’’

That scarcity, in turn, means that trades for front-of-the-rotation starters typically require a wrecking ball taken through a team’s young core. That approach is one that the Cubs resisted, and that the Red Sox likewise seem disinclined to entertain, resulting in rotation-building through a mixture of big-ticket free agency and opportunistic trades.

In other words, while Lester in one way highlights how the Red Sox and Cubs took different approaches with one pitcher, in another way, he demonstrates a form of similarity that exists between how the two clubs are approaching their rotations.

Follow Alex Speier on Twitter at @alexspeier.