Choi Jin Hyuk left his two-year mandatory military service earlier than expected. He was discharged due to a serious knee injury.

The actor enlisted on March 31, 2015, but after five weeks of basic training, injured his knee. At the time his agency, Red Brick House, issued a statement about his injury.

"Choi Jin Hyuk suffered a knee injury during training. He went to the hospital to get his knee treated."

According to his agency, Choi's knee problems pre-dated his enlistment but he did not think the problems would interfere with his service. Knee injuries tend to recur, leading what was once a minor injury to worsen and eventually require corrective surgery.

Choi was hospitalized and underwent surgery but given the severity of the injury, his rehabilitation was lengthy. On October 16, he was discharged on medical leave. National Defense Ministry rules state that an injured soldier can take medical leave of up to one month with possible extensions depending on the patient's condition.

His agency released a statement about the discharge on October 21.

"Choi Jin Hyuk was discharged for an injury on October 16. Due to severe damage to the cartilage in his knee, Choi Jin Hyuk received cartilage stem cell transplant surgery on his left knee. The army decided it would be hard to serve any longer due to his need for long-term treatment and rehabilitation, so he received the notice for his disability discharge."

Choi wanted to continue serving after his surgery. His agency said that he was not happy with the way things turned out.

"His will to serve was strong and sincere, so he is extremely heartbroken due to this unexpected situation. The agency is sorry to deliver such news. From here on Choi Jin Hyuk plans to focus on his treatment and recovery."

Choi originally had the option of enlisting in the promotional unit of Seoul Metropolitan Police Agency. However, he declined to accept this special enlistment term, which would have been less physically demanding, and chose instead to serve his mandatory enlistment in active duty.

Before enlisting Choi appeared in the dramas "Emergency Couple," "The Heirs" and "Fated to Love You."