Butler (undisclosed) was placed on injured reserve Tuesday, Field Yates of ESPN reports.
Butler, who spent the first four years of his career in New England, joined the Cardinals last season after three years in Tennessee, but he ultimately decided to retire without playing a regular season game for Arizona. He returned to the Patriots on a two-year deal in March with expectations that he'd compete for a starting gig. Now Butler will be forced to miss a second straight season, this time due to an undisclosed injury. The 32-year-old did play in the Patriots' preseason loss to the Giants on Thursday and recorded a tackle.