play second fiddle
US /pleɪ ˈsɛkənd ˈfɪdl/
UK /pleɪ ˈsɛkənd ˈfɪdl/

1.
estar en segundo plano, ser secundario
to be in a subordinate or less important position than someone else
:
•
She's tired of always having to play second fiddle to her older sister.
Está cansada de tener que estar siempre en segundo plano con su hermana mayor.
•
He's a talented musician, but he always seems to play second fiddle in the band.
Es un músico talentoso, pero siempre parece estar en segundo plano en la banda.