Giants at 58-83 Are on Pace for Largest BaseRuns Gap Since 2002

At 58-83, the 2026 San Francisco Giants have not spent a single day above .500, and according to Jay Jaffe, they are flirting with a particularly unglamorous distinction: the largest gap between actual wins and BaseRuns-projected wins of any team since 2002.

What BaseRuns is measuring

BaseRuns is a second-order win estimator. Where the familiar Pythagorean formula uses actual runs scored and allowed, BaseRuns derives estimated run totals from underlying components: hits, walks, hit-by-pitches, stolen bases, and similar inputs. Those estimates are then fed into the Pythagenpat formula, a variant of Bill James's Pythagorean model in which the exponent is itself a function of the scoring environment, expressed as X = ((RS + RA)/G)^0.287. The result is a second-order expected winning percentage that attempts to strip out sequencing luck and other noise sitting between a team's raw production and its actual record.

Historical BaseRuns data runs back to 2002, and within that window the Giants currently rank fourth on the all-time list of teams whose actual record most severely underperforms the model — with a couple of other 2026 teams reportedly keeping them company near the top of that list, per Jaffe's piece.

The season that was supposed to be different

The gap is especially striking given the offseason investment. Per Jaffe, Buster Posey — the Giants' president of baseball operations — hired Tony Vitello away from the college ranks to manage the club, then added free agents Luis Arraez and Harrison Bader to address weak spots in the lineup. A full season of Rafael Devers, acquired mid-season the year prior, was also part of the calculus. The expectation, reasonable enough on paper, was a return to the playoffs for the first time in several seasons — only the second postseason appearance in the past 10 seasons, per Jaffe.

Instead, the Giants own the National League's second-worst record. Posey confirmed earlier this week that Vitello will return as manager in 2027 despite the difficult debut season, so the organizational commitment to the current direction appears intact even as the on-field results have diverged sharply from what the underlying numbers suggest the roster deserved.

What to watch

The Giants are not alone in this particular misery. Jaffe's piece draws a parallel to the Tigers, who are reportedly nearly 11 full wins short of their Pythagorean-projected win total — the third-largest such shortfall in the Wild Card era. Both teams are, in their own ways, case studies in how badly a season can go sideways even when the underlying production tells a more forgiving story.

The model says the Giants were better than this. The standings, so far, have disagreed.