Contesting at the first MXGP World Championship of the season in Argentina, Nagl damaged his knee during the first moto.
The tough German tried to race the second moto but had to pull out after a few laps due to the pain.
It’s now been revealed that Nagl has torn a ligament in his knee and will undergo surgery on Monday.
It’s a shame because it looks like a lengthy spell on the sideline for the Sarholz KTM rider.
The team posted the following update on social media:
Pic: Scott Dunne