YOU SAID:

He would likely play by his rules unless he was prompted.

INTO JAPANESE

彼は促されない限り彼はおそらく彼のルールで遊ぶでしょう。

BACK INTO ENGLISH

He will probably play according to his rules unless he is prompted.

INTO JAPANESE

彼は促されない限り彼はおそらく彼のルールに従ってプレーするでしょう。

BACK INTO ENGLISH

He will probably play according to his rules unless he is prompted.