Aaron Shingler, Matthew Rees and Liam Williams return to the Scarlets while Alun Wyn Jones and James King will head back to the Ospreys.
Lou Reed and Lloyd Williams go back to Cardiff Blues.
Jones and Lloyd Williams both featured off the bench in Wales’ Six Nations victory over Italy in Rome but Howley is keen for them to have more match time in the RaboDirect PRO12 this weekend.
