Conner Mantz, the fastest American marathoner on the planet, announced Tuesday that he is withdrawing from the April 20 race after his fitness failed to recover in time.
“Unfortunately, my fitness has not progressed well enough for me to be able to race the upcoming Boston Marathon at my best. I am very disappointed but look forward to being back racing soon.”
The news lands hard for American running fans who had been hoping to see Mantz compete at the storied race after a breakout 2025 that made him the talk of the sport.
A Record-Breaking Year Gone Sideways
To understand how significant this withdrawal is, you need to know what Mantz accomplished in the 12 months prior. At the 2025 Boston Marathon, the 29-year-old Utah native finished fourth with a personal best of 2:05:08 — the fastest time ever run by an American on the Boston course. Six months later at the 2025 Chicago Marathon, he went even faster, clocking 2:04:43 to shatter the American marathon record. He also holds the American half marathon record, set at the 2025 Houston Half Marathon. In the span of a single year, Mantz had rewritten what Americans thought was possible in the marathon.
He was announced as a headliner for Boston 2026 alongside defending champions John Korir and Sharon Lokedi and fellow American record holder Emily Sisson. A race between Korir and a fully fit Mantz would have been a must-watch.
An Injury That Never Fully Healed
The trouble began shortly after his Chicago record. Mantz picked up a bone stress injury that forced him to skip the Houston Marathon and the USATF Cross Country Championships. By mid-February, he had only just returned to structured training — posting a workout on Strava that showed he was back on the track but clearly still rebuilding.
At the time, he was cautiously optimistic. When asked in comments whether he planned to race Boston, his answer was measured: “As long as another injury doesn’t come up.” With just over nine weeks until race day, it was always going to be a tight timeline.
It wasn’t tight enough.
What It Means for the Race
Mantz’s absence reshapes the American story heading into Patriot’s Day. The men’s field still features reigning champion John Korir and a deep international lineup, but the domestic angle loses its headline act. For fans of American distance running, this is a real blow — Mantz had been the most compelling figure in the sport heading into 2026.
The good news is that he’s young (29), supremely talented, and made clear he intends to return to racing. His record of 2:04:43 isn’t going anywhere, and neither is his ceiling.
Boston will still deliver a world-class race on April 20. But for a lot of running fans, one name will be noticeably missing from the start line on Hopkinton Green.
