"Tomorrow and during our upcoming match in Budapest (November 1-2) I will cheer on my team Energy Standard from the stands.
Unfortunately, I have had some minor back problems in recent days and I follow the medical advice to rest.
I am still training well and look forward to competing again ", the swimming star writes on his Instagram.
ISL is a mixed team competition in short course (25-meter pool) with ten teams that meet in matches and collect points.
The basic series is decided in October-November and then the eight best teams reach the semifinals.
The four best teams from there will then compete in the final later in November.