First, if you mean the word "winner" to indicate someone who got the best rating in something, or say "win first prize", it will be 優勝者(ゆうしょうしゃ) in Japanese. Not ゆうしゃ, no winner has a sword like virtual games:p We distinguish between winning a simple game and getting the best prize, who has done the former will be 勝者(しょうしゃ). Next, the word "judge", it of course means someone who make a judge, but 裁判官(さいばんかん) means an adjudicate and 審判(しんぱん) means an official almost only at a sports contest. Considering its context, I guess you want to mean just a person who decides the results of a competition. In such case, 審査員(しんさいん) will be the best choice. And the word "select"... You probably mean to say 選択されます(せんたくされます). However, it sounds more "choose" like, and considering its context, it will be more suitable if you consider it as "elect", which is 選ばれます(えらばれます) in Japanese. Finally, the whole sentence will be 優勝者は審査員によって選ばれます(ゆうしょうしゃは しんさいんによって えらばれます).

勝者は、審判が選びます。(shousha ha shinpan ga erabi masu.)

勝者は審判によって選ばれます。 （syousha ha sinpan niyotte erabaremasu) I think ●winner=the person won the game. 　勝→win,　者→the person　in Japanese ●select→選 ぶ（era bu),選択する(sentaku suru) is selected(passive)→選 ばれる(era bareru) ×選択される(sentaku sareru) I don't hear "sentaku sareru" in Japanese when I use [is select] as passive. ●judge→審査員(shinsain) (ex)at the contest →審判（shinpan)　 (ex)at the sports game 審査員and審判 is same mean.

You mean: **The winner will be selected by the judges.** 勝者は審判に決められること。