In an official notice via NU'EST official website, Pledis Entertainment stated, "Last week, Aron experienced pain in both of his shoulders as well as his arms, and immediately visited the hospital to receive a checkup; according to the doctor, Aron needs plenty of rest while focusing on recovery treatment. He is currently focussed on recovering his health."
The label continued, "We will continue to monitor Aron's condition per the doctor's advice, and while we are still discussing the matter of Aron's participation in NU'EST upcoming 2019 concert 'Segno in Seoul' set to take place from April 12-14, we feel that performing on stage for over 3 hours may be difficult in his current state. Despite this, due to Aron's strong wishes to stand on stage for the fans who have been waiting for him, he will participate in the concert to an extent so that he does not strain his injury. Still, while Aron's current state is overall good, he will participate in stages which include performance and choreography while sitting in a chair as to keep his movements to a minimum, and he will sit out certain stages."
Finally, Pledis Entertainment asked fans for their understanding. We hope you get well soon, Aron!