Haussler crashed in training last November and has been struggling through surgery and rehabilitation in an attempt to return to racing.
”All I can really say is that I still have problems with my knee and I'm doing many different therapies, exercise and physio to try to resolve the problem so I can start racing again," Haussler said.
Bahrain Merida revealed Haussler is undergoing physiotherapy with electric waves, localized shock waves and manual therapy.
“All specialists that he has seen, including an arthroscopic surgeon, with proposed therapies, can’t give an exact date for his return," team doctor Carlo Guardascione said.
"We will need to be patient and see how it will go in the following weeks and how the knee reacts with the proposed therapies and adequate training program.”
Last year, Haussler finished 7th in Milan-San Remo and 6th in Paris-Roubaix before making the end of season switch to Bahrain-Merida after IAM Cycling folded.
He was hoping to replicate those performances in the 2017 spring classics but the exact date of his return will now remain uncertain for some time.
"It has been going on for many months now but I am doing everything possible to get back to a level where I can start racing again.
"I'm back on the bike at the moment and small steps have been made but I will still need some more time to heal 100 per cent.”