The San Francisco Giants’ 2010s Dynasty Didn’t Follow The Rules. Neither Has Their Rebuild.

A decade ago, the San Francisco Giants built one of the strangest dynasties in baseball history — winning three World Series in five seasons while also missing the playoffs (and sometimes finishing below .500) in each of their non-championship seasons. That dynasty officially came to an end after San Francisco lost the 2016 Division Series to the eventual champion Chicago Cubs, with the team tumbling to 64-98 the following year. But baseball’s weirdest dynasty was never going to transition into a conventional rebuild. So instead of fading away, the Giants have remained surprisingly competitive even after their glory years ended — especially this season, as they lead the National League West over the favored Los Angeles Dodgers and San Diego Padres (for now). And they’ve done it with one of the most unique roster constructions in MLB today.

Last year’s Giants weren’t supposed to be much of a playoff threat at all — particularly with longtime manager Bruce Bochy retiring, iconic pitcher Madison Bumgarner departing for the Arizona Diamondbacks and Cooperstown-bound catcher Buster Posey opting out of the season over COVID-19 concerns. But they hung around for an impressively long time in the expanded postseason race, with over a 60 percent chance to make the playoffs as late as the second week of September. Only a late-season swoon — losses in 10 of their final 16 games — prevented the Giants from grabbing the No. 8 seed in the NL playoff bracket, as they lost out on a tiebreaker to the Milwaukee Brewers.

Still, it had been an encouraging season in San Francisco, if for no other reason than the emergence of a deep supporting cast that carried the team in Posey’s absence. Outfielder Mike Yastrzemski grabbed headlines for reviving the family legacy¹ with an eighth-place MVP finish, but his was far from the Giants’ only breakout performance of 2020. Ten different members of the Giants played at a 2.0 wins above replacement² pace or better per 162 games, tying San Francisco for fifth in MLB in that regard. The producers were a mix of newcomers and holdovers, castoffs and old favorites from the dynasty era, but they helped San Francisco improve from 26th in WAR in 2019 to 14th in 2020 — with a particular boost coming on the hitting side (where the Giants rose from No. 28 in position-player WAR to No. 7).

Giants pitching still appeared to be an issue going into 2021, however. San Francisco’s staff had finished 24th in WAR last season, including 23rd among starters and 25th among relievers. Although baseball-ops boss Farhan Zaidi applied his roster-churning approach to the problem — adding Anthony DeSclafani, Alex Wood and Aaron Sanchez to the rotation, and Jake McGee, Matt Wisler, Zack Littell and José Álvarez to the bullpen over the offseason — nothing about the Giants’ staff exactly struck fear into the rest of the National League.

Perhaps it should have, though. Because here we are, more than six weeks into the 2021 season, and San Francisco currently has the best starting rotation in baseball according to WAR, beating out the Dodgers and Brewers for the top spot.

A team rising from No. 23 to No. 1 in rotation strength is pretty unprecedented. Since the dawn of the expansion era in 1961, the biggest year-over-year improvement for a team who ranked first in starting pitching WAR came from the 1980 Philadelphia Phillies, who had ranked 21st in 1979. (They and the 1971 Chicago White Sox are the only teams in the era to go from outside the top 16 in rotation WAR to No. 1 overall the following season.) Even if the Giants’ rotation fell to second place, they would join the 2009 Atlanta Braves, 1989 California Angels and 2020 Philadelphia Phillies as the only teams to rise to No. 2 in rotation WAR from No. 23 or worse the season before.

Either way, it’s been a significant turnaround. And what’s particularly notable is that the Giants basically built this rotation in the span of just a few seasons. While the always-entertaining Johnny Cueto has been with San Francisco since 2016, and Logan Webb made his debut late in the 2019 season, the rest of the Giant starters were acquired over the past two offseasons. As a result, 85 percent of the wins generated by San Francisco pitchers have come from players who were not homegrown — i.e., they made their MLB debuts with teams other than the Giants. Among teams this season, only the Texas Rangers (90 percent) have a higher rate of production from pitchers developed outside the organization — but they haven’t been nearly as successful with the strategy, ranking 24th in WAR from starters and 22nd in pitching WAR overall.

San Francisco’s rebuilt bullpen hasn’t quite fared as impressively as its rotation. Giant relievers rank 27th in WAR, with a collective ERA 10 percent worse than league average. With the exception of Tyler Rogers, who is putting up unexpectedly dominant numbers (0.76 ERA) as a setup man, the rest of the San Francisco relief corps has been largely mediocre — as exemplified by the 5.09 ERA carried by McGee at closer. Still, the Giants have MLB’s 13th-best pitching staff by WAR overall, in no small part because of how much they’ve relied on the rotation; they’re tied with the Dodgers for the MLB lead in innings per game by starters, a testament to how Kevin Gausman, DeSclafani, Webb, Wood, Cueto and — when healthy — Sanchez have been giving the team a fighting chance every game.

It helps that, on the hitting side, the 2021 Giants have been every bit as good as they were in last season’s breakout campaign — though with a slightly different mix of players driving their success. For instance, while Yastrzemski has been plenty good, with an OPS 20 percent better than average, he has not quite replicated his MVP-level production from a year ago. But Posey has returned with a vengeance, leading all catchers in WAR so far this season, and shortstop Brandon Crawford — a cornerstone of the dynasty era who’d fallen off in subsequent years — is tracking for the best season of his career (5.6 WAR per 162) so far in 2021.

Both Crawford and Posey are also 34 years old this season, and they’re not even the oldest of San Francisco’s regular contributors. (Cueto and third baseman Evan Longoria are 35 this year.) So maybe the most unique thing about this Giants team is just how ancient it is by modern baseball standards. These days, the majority of teams try to go young and exploit the fact that, under MLB’s current economic system, players in the early phase of their careers provide far more bang for the buck than their older counterparts. But the Giants have gone in the opposite direction: Already the second-oldest team of 2020 (behind the Minnesota Twins) at 29.7 years old,³ they got 1.8 years older in 2021, easily becoming MLB’s oldest team. Among teams who ended up being 31 or older on average, that’s MLB’s seventh-biggest year-over-year increase in average roster age since 1901:

With that, the Giants are also the first team since the 2014 Phillies with an average age over 30 for both their batters and pitchers. Moreover, a staggering 82.2 percent of San Francisco’s wins have been generated by players aged 30 or older, which would rank fifth-highest in MLB since 1901. (No other team in 2021 is above 62 percent in that regard.)

When teams rebuild after a successful run, we usually think about it in terms of a cycle: As the aging core of the previous team loses effectiveness, the team shuffles in younger talent and prepares for its next window of competitive opportunity. So it’s rare to see a team like the 2021 Giants, who have rebuilt from the ashes of a dynasty with a team even more veteran-laden than the one that last won them the World Series. 

Then again, it’s also rare to see a team cobble together the best rotation in baseball out of mostly unheralded pitchers who hadn’t been with the club just a few seasons earlier. There are plenty of questions about how viable all of this will end up being — our forecast model doesn’t really consider San Francisco a serious title contender yet, despite its impressive record — but for now, the Giants are the dark horse in a division that was supposed to belong to their rivals to the south. And just like how they ran their dynasty a decade earlier, they’ve done it in an unorthodox way while catching everybody by surprise.

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