CHICAGO — There was once a time — you know, like, three weeks ago — that the Toronto Blue Jays fielded one of the oldest position player rosters in the majors. Danny Jansen and Isiah Kiner-Falefa were both 29. Kevin Kiermaier was 34. Justin Turner was and still is the oldest hitter in the league at 39.

These days? They’re one of the youngest. Spencer Horwitz and Will Wagner are 26. Steward Berroa, Davis Schneider, Joey Loperfido, Alejandro Kirk, and, somehow, Vladimir Guerrero Jr. are all 25. Addison Barger and Leo Jimenez are even younger. The only guys over 28 are Brian Serven (29) and George Springer (34).

Now, there’s no real benefit to being generally young or old in this league. The nine oldest groups of position players — led by the 71-51 Los Angeles Dodgers — are all either in post-season position or within three games of one. Three of the five youngest can claim that, too. True talent, 40-man depth, and a balance of players at different stages of their careers — young players with energy and upside, prime players who perform reliably, and veteran players with experience in the game’s most stressful situations — is what wins.

Entering the season, the Blue Jays thought they had all three of those elements. Eight games under .500 in the middle of August, you could argue they had none. Regardless of opinion, the Blue Jays roster we’re watching today is unquestionably weighted towards the young, unproven, energetic end of the spectrum. And as they grind through a relentless August with early-October vacations awaiting, that vim and vigour certainly helps.

Jimenez hitting his first big-league homer Monday in Anaheim and, four days later in Chicago, homering again gives everyone a jolt. Wagner entering the fold and beginning his MLB career with hits in seven of his first 12 plate appearances sends energy through the dugout. Ernie Clement, not exactly boyish at 28 but nevertheless an honourary member of the Blue Jays youth movement, taking on an everyday role and having more multi-hit games (eight) than hitless ones (four) over his last 20 is provocative. It gets the people going.

“They’re all playing hard,” Blue Jays manager John Schneider said before Friday’s game. “I think you get to the dog days of August and that can be tough when you’re not in it. But the energy that they have every day has been cool to watch. And watching guys like George [Springer] and Vlad [Guerrero Jr.]  take them under their wings has been cool, too.”

Friday, in a rollicking, 6-5 loss to the Chicago Cubs in the opener of a three-game set, you saw it all. Young players experiencing big moments (Jimenez homered; Wagner had two hits) and learning ones (Jimenez got over-aggressive and struck out in a critical late-game spot; Wagner booted a routine groundball that could have ended an inning).

And veterans providing mettle at pivotal times, like Springer, who tripled off Hector Nerris with two out in the ninth to tie the game. Or Guerrero, who made a pair of stellar defensive plays late, handling a tough hop to help Brendon Little get a much-needed out after allowing a homer in the seventh, and reaching into Toronto’s dugout to corral the final out in the bottom of the ninth.

“They’ve been awesome,” Schneider said pre-game of Springer and Guerrero. “You go from a really, really veteran team to not overnight. And they’ve been as good as we could have hoped, really. Them, starting pitching, they’ve kind of carried the weight a little bit. But it is nice to see them mentor some guys, if you will.”

Ultimately, the Blue Jays fell in the bottom of the 10th, when Seiya Suzuki shot a 2-2 Chad Green slider through the left side of the infield to plate the winning run. In the top half, Guerrero Jr. and Kirk made outs on hanging breaking balls — Guerrero’s sounded like a homer off the bat and — and Horwitz fouled off a first-pitch, middle-middle fastball. The Blue Jays had opportunities; in some cases, created them. But the best teams capitalize consistently.

“The fight has been there the entire year,” Schneider said after the game. “[Guerrero] just missed a couple today.”

But these games aren’t really about the wins and losses, are they? They’re about the continued maturation process of young players who went from riding busses in triple-A to, only weeks later, playing before nearly 40,000 at one of baseball’s most iconic ballparks. When Cubs starter Kyle Hendricks began his MLB career in 2014, many of the Blue Jays he faced on Friday were in their early teens.

Of course, Hendricks did what he does, mixing sinkers in and changeups away to righties, with sinkers up and changeups away to lefties, to produce a torrent of soft contact over his five innings. He allowed only two balls in play over 100 m.p.h. and earned 11 of his 15 outs on the ground.

The Blue Jays were mostly stymied by that approach on a hot, humid Wrigleyville afternoon. They were gifted an unearned run in the fourth, as the Cubs middle infield botched plays on three consecutive soft groundballs that could have ended the inning. And Jimenez golfed a well-located sinker down-and-in to left for a solo shot. But that was the only extra-base hit they mustered off Hendricks, whose fastball sat 87 on the day.

Meanwhile, Blue Jays starter Yariel Rodriguez continued to provide mixed results in his 13th MLB outing. He may have had his best stuff of the season, setting a season-high with 14 swinging strikes — five off fastballs, five off sliders, four off splitters. He used his fastball effectively at the height of the zone and got the Cubs to chase nearly half the sliders and splitters he threw off the plate.

But he hung a number of breaking balls — a hallmark of Rodriguez’s MLB starts thus far — like the one he left up to Cody Bellinger in the first and watched the Cubs outfielder rocket 404 feet over the right-field ivy. 

Rodriguez paid for it again in the fifth when Pete Crow-Armstrong hammered a full-count slider that landed not far from where Bellinger’s did. And four pitches later, Miguel Amaya went 426 feet to deep-deep left-centre off an elevated heater he’d already seen twice in the at-bat. 

“It’s just executing, really. You look at his outings and his stuff is usually there. It’s just a couple of mistake pitches,” Schneider said. “For him in particular, it’s about not taking a pitch off and remembering what his stuff is capable of.”

For his part, Rodriguez says his curveball is the pitch that needs the most refinement going forward. And he’s right — on Friday he left four over the heart of the plate, including the one Bellinger hit out in the first. But he backed up a few sliders, as well, and got away with more mistakes than anyone ought to expect him to going forward:

“I felt good. My pitches, they all were working for me. Everything was working great,” Rodriguez said through Blue Jays interpreter Hector Lebron. “But I threw three pitches right down the middle — and I paid for it.”

So, a mixed bag for the Cuban right-hander, who’s still acclimating to a starting role he last consistently served in five years ago, against the highest level of competition he’s ever faced, on a new continent, and nearing the most innings he’s thrown in a season since 2021. There will be growing pains. For Rodriguez and for everyone.