Poor defensively, the young Rovers were punished as West Brom lead 4-0 going into the break.
By the hour mark the home side had made it five on an afternoon to forget.
Rovers grabbed a consolation goal with 15 minutes to go, Matty Platt, who had impressed as a second half substitute, rising highest to head home a Lewis Hardcastle corner.
It got worse for Rovers as they ended the game with ten men. Hardcastle receiving his marching orders after a clash with an Albion player.
"It was hugely disappointing end to the season," said coach David Lowe. "We looked lethargic, it was a typical end of season display.
"We've watched the game again and it wasn't good viewing, it was a poor defensive performance from us from front to back."
ROVERS: Williams, Nyambe, Doyle (c), Bauress, Scott (sub Tomlinson 68 mins), Edo (Platt 46 mins), Green, Hardcastle, Preston, Joel, Wall (sub Cham 45 mins).
Subs not used: Fisher, Howarth.