Luckily, this player's sp was not auto-assigned before he was sold.
However, today I found that accumulated sp of another player have already been auto-assigned. I am not sure, but believe that these sp were auto-assigned after I could not attend the last league match yesterday. Similar cases occurred before in this team, but none for my other team in same server. I used new android apps for this team. I likely did not log out before un-installing.