Scott Wootton has vowed to come back stronger after he ruptured his anterior cruciate ligament against Barnet on Tuesday night.
The 24-year-old signed for Dons in the summer and only made four appearances for his new club before colliding with keeper Lee Nicholls on Tuesday night, causing the injury.
Wootton, who scored the winner in a 1-0 win at Rochdale, is expected to be on the sidelines for nine months, almost certainly ruling him out for the rest of the season.
“I’m devastated if I’m honest,” Wootton told mkdons.com. “It’s incredibly frustrating, especially after I felt I had made a good start to life here at MK Dons – I was really enjoying it too.
“I know I’m in very good hands with the staff here and we’ll do everything we can together to ensure I come back stronger and a better player.”
Dons’ medical staff have experience in deal with cruciate ligament injuries. Last season, Rob Hall suffered a similar injury and was working with physio Simon Crampton on his rehabilitation before moving to Oxford United in the summer. And more recently, Chuks Aneke joined Dons just a few days before Wootton and is currently in the final stages of his recovery and is expected back within two months.
Boss Karl Robinson added: “This news has rocked us all – we are gutted. Despite only being with us for a short time, Scott has made a big impression both on and off the pitch.
“He’s a leader and well liked by everyone so this is a difficult one to take, but knowing Scott like I do, he’ll come back even bigger and better than before.”