Marquez signed a minor-league contract with the Astros on Sunday.
Marquez missed two seasons following shoulder surgery and struggled upon his return last year, posting a 4.99 ERA and 44:38 K:BB over 30.2 frames across four levels in the minors. The left-hander will turn just 25 next month, though, so the Astros felt the former top prospect was worth a roll of the dice.