跑龙套 (pǎo lóngtào) play an insignificant role

Usage:

“跑龙套”本义是指戏曲中拿着旗子演士兵的角色。后来用来比喻在别人手下做一些不重要的事情,或者在一个团队、项目中充当不重要的角色。
"跑龙套(pǎo lóngtào)" refers to the person who holds flags and plays the soldier’s role in the opera. It is a metaphor for those who are in charge of something unimportant or play a small role in a team or a project.

Sentences:

1、Zhōu Xīngchí shì zhōngguó zhùmíng diànyǐng míngxīng, èrshí duō nián qián tā yě shì cóng pǎo lóngtào kāishǐ de.
周星驰是中国著名电影明星,二十多年前他也是从跑龙套开始的。
Stephen Chow is a famous film star in China. He began his career by playing the walk-on part more than twenty years ago.

2、Wǒ zhǐ shì gè pǎo lóngtào de. Zhègè xiàngmù shì Lǐ Míng fùzé de, nǐ kěyǐ wèn tā.
我只是个跑龙套的。这个项目是李明负责的,你可以问他。
You can ask Li Ming, for he is in charge of this project. I am just a utility man.

原文链接