Turns out, former NFL player Blake Proehl is good on the gridiron AND on the keys ... 'cause he performed so well on the piano during his recent "American Idol" audition -- he brought Katy Perry to tears!!
The ex-Minnesota Vikings wideout -- who's the son of longtime Panthers receiver Ricky Proehl -- sang his heart out in front of Perry, Luke Bryan and Lionel Richie on the famed talent show ... and when his segment aired on TV on Sunday, it wasn't hard to see the dude's got a bright future in music.