Marcel Hug, the defending champion in the men's wheelchair race, has withdrawn from the Boston Marathon.
Hug, of Switzerland, made the announcement just hours before the start of the race. No reason was given for his withdrawal.
Sho Watanabe of Japan also withdrew. Watanabe finished ninth at last year’s Boston Marathon.
Hug is the reigning men’s wheelchair division champion, five-time Boston winner, and course record holder. Hug won the marathon last year despite making a wrong turn in the final mile, finishing the slightly detoured route just seven seconds off his course record.
Hug, who has raced Boston eight times and has five victories here, cost himself a $50,000 course record bonus when he missed the second-to-last turn, following the lead vehicle instead of turning from Commonwealth Avenue onto Hereford Street.