Sjöström swam in the first two matches in ISL for her team Energy Standard, but then returned to Stockholm to train after the elbow injury that stopped her for four months earlier this year.
Then her message was that she would return to the competition pool and the playoffs in ISL in November.
But the desire to compete became too strong - and the Olympic silver medalist in the 50 meter freestyle in Tokyo has changed.
Energy Standard has its third match this weekend and ends the basic series with another match Thursday-Friday next week.