The Canadian time trial champion will require six weeks to recover and will miss out on her goal of competing in the time trial and road race at the UCI Road World Championships in Yorkshire.
"Sad to report that my 2019 season is over after a hard crash in stage 1 of the Boels Ladies Tour," Kirchmann wrote in a post on Twitter.
"I finished the stage, but felt afterwards that something wasn’t quite right with my knee. A scan showed damage to my MCL that will require at least six weeks of recovery."
Kirchmann has had an outstanding season with her Sunweb team. She has secured victories in the time trial at the national championships and at Grande Prix Cycliste de Gatineau, and podium finishes at Omloop van het Hageland, OVO Energy Women’s Tour, Postnord Vargarda West Sweeden TTT and the Ladies Tour of Norway.
She was fourth in the time trial at last year's Innsbruck World Championships.
"I was feeling strong on the bike and looked forward to challenging myself in the final races of the season, especially at the upcoming World Championships in Yorkshire," Kirchmann wrote.
Kirchmann said that with her season over, she will turn her attention to a full rehabilitation for her knee while also looking further ahead to next season.
"I’m still grateful for all the good memories racing with the team this season, and can’t wait to get back on my bike."
#injuryupdate ⬇️🚲 pic.twitter.com/62GEOj0eQhSeptember 9, 2019