The Chiefs placed Santos (groin) on injured reserve Tuesday, Ian Rapoport of NFL Network reports.
According to Terez A. Paylor of The Kansas City Star, Santos, who missed three weeks of training camp with a groin injury, was kicking for the Chiefs during the first three weeks of the season while still recovering from the issue. While the injury didn't seem to hinder his performance -- he made all 12 of his extra-point attempts and all three of his field-goal tries -- Santos was on the receiving end of a big hit in Sunday's win over the Chargers, which may have presented further aggravation. The extent of Santos' setback is unclear, but it's conceivable that he could be one of two players the Chiefs elect to reinstate from IR once he spends at least eight weeks on the inactive list. In the meantime, the Chiefs signed Harrison Butker to fill the void at kicker, and he could be of immediate intrigue in most formats given the potency of the Kansas City offense this season.