On January 8th, Josh “NintendudeX” Atkins suffered a seizure in his sleep. He was rushed to the hospital immediately and a battery of tests was conducted. Josh was released later that night, pending test results. After the tests came back devoid of immediately pressing issues, life hesitantly returned to normal at the Fusion house.
Five days ago NintendudeX suffered another attack in his sleep. Upon being discharged from the hospital he was prescribed a seizure medication that will take a toll on his health and his lifestyle until he can adjust to it. With this in mind, the team, Josh, and the management all decided that it would be best for Josh’s health if he took some time off from the stress of professional play. When Josh feels able to return, his spot will be waiting for him.
Five days ago NintendudeX suffered another attack in his sleep. Upon being discharged from the hospital he was prescribed a seizure medication that will take a toll on his health and his lifestyle until he can adjust to it. With this in mind, the team, Josh, and the management all decided that it would be best for Josh’s health if he took some time off from the stress of professional play. When Josh feels able to return, his spot will be waiting for him.
Source
I don't remember him being all that great when he was in the LCS but it looked like he was playing decently well in the challenger stuff. NACS starts on Feb 18 so there's not that much time for them to finalize a sub and get a lot of practice together.