On September 5, 2026, the San Francisco Giants beat the New York Mets 9-5 in Queens, salting away a comfortable road win. The offensive story wasn't Christian Koss's regular contributions — the 28-year-old third baseman entered the day hitting .211 on the season — but what happened twice in the same game: he hit two home runs, matching a third of the total he'd hit across 128 career games before that afternoon.
Koss's two homers didn't just beat the average — they obliterated it. Across every player who took the field on September 5, the mean number of home runs was 0.138, meaning most hitters, on most days, don't hit any at all. Koss's night produced a z-score of 4.90 against that population, a mark so far outside the normal range that performances like it happen only a handful of times across an entire big-league season — the kind of outing you'd expect from one specific player once every few years, not something that shows up regularly across 30 teams on any given night.
Here's the honest complication: the batted-ball data for these two specific home runs — exit velocity, launch angle — isn't available in what's on record for this game, so there's no clean answer for the mechanical 'how.' What is on record is Koss's season line: a .310 slugging percentage and .563 OPS across 52 games, the profile of a hitter who hadn't shown much power in 2026. He'd hit exactly one home run in the 51 games before this one. A light overall power hitter suddenly producing a two-homer game usually points to mistake pitches turned into contact or a favorable matchup, but without pitch-by-pitch detail from the game, that's an educated read rather than a confirmed cause.
Here's the honest complication: the batted-ball data for these two specific home runs — exit velocity, launch angle — isn't available in what's on record for this game, so there's no clean answer for the mechanical 'how.' What is on record is Koss's season line: a .310 slugging percentage and .563 OPS across 52 games, the profile of a hitter who hadn't shown much power in 2026. He'd hit exactly one home run in the 51 games before this one. A light overall power hitter suddenly producing a two-homer game usually points to mistake pitches turned into contact or a favorable matchup, but without pitch-by-pitch detail from the game, that's an educated read rather than a confirmed cause.
Zoom out and the number gets stranger. Koss came into the day with six home runs in 128 career games; two of those six landed in this single contest against the Mets — roughly a third of his career power output packed into one afternoon. His season OPS of .563 sits well below league-average production, and 39 strikeouts in 52 games this year describe a bat-to-ball utility infielder, not a slugger. That context is exactly why the z-score reads so extreme: it's not just measuring a big offensive day, it's measuring how unlikely that day was for this particular hitter.
The question worth tracking isn't whether Koss becomes a power threat — his track record argues against it — but whether the Giants give him more time at third base down the stretch to see if anything real shifted in his approach. Watch his next ten games: another extra-base hit or two would hint at an adjustment, while a return to singles and walks would confirm that September 5 was exactly what the numbers suggest — a one-night outlier sitting far outside his normal range.
Either way, for one night in Queens, a .211 hitter with a career slugging percentage barely above replacement level looked exactly like someone he probably isn't.