MMA fighter Christian Lohsen of the Professional Fighters League just revealed he had to have a testicle removed after it ruptured during training this week ... and the crazy part??? He's already cracking jokes about it!!!

The 26-year-old out of Florida shared the cringeworthy news on Thursday ... saying, "So, last night was rough ... in a training accident I got my left testicle ruptured by a knee which led to it getting surgically removed."

Lohsen says the procedure went well and he's at home and recovering ... adding the loss will not result in loss of testosterone or ability to have kids.

While the incident sounds serious, Lohsen has maintained a sense of humor throughout the whole ordeal ... saying, "If I lose the other one however it's a different story, so from now on if you hit me in my last testicle we aren't friends ... lol."

The 9-2 fighter added a couple of clever hashtags ... saying, "#NoNutNovember #OneBallWonder #MMAIsADangerousGame #TookNoNutNovemberWayTooFar"

Lohsen has won 5 of his last 6 fights ... losing to J.J. Okanovich in the Dana White Contender Series in 2019.