Santos missed four field goals in the Titans' 14-7 home loss to the Bills. He misfired on a 50-yard field goal in the second quarter and a 36-yard attempt with 49 seconds remaining before halftime.
The Bills blocked a 33-yarder in the fourth quarter and Santos later botched a 53-yard field goal as the Titans fell to a 2-3 record this season.
After the game, Titans head coach Mike Vrabel voiced his support for Santos despite the four-miss day.
"I have confidence in him," Vrabel told reporters Sunday. "... I think we all have a job to do. We like to think that if you make mistakes, we can get them fixed and corrected. This is a guy who's made some kicks for us. We'll have to do a better job making them, and coaching him, and executing them."
Santos, 27, has converted 4-of-9 field goals and all 12 of his extra points this season. He called his performance against the Bills "very painful."
"It was a very painful, extremely disappointing day," Santos told reporters Sunday. "I don't feel sorry for myself, I feel sorry for my teammates and coaches that work hard all week, including myself. I feel sorry for my teammates, my coaches and they deserve to win and I have just got to do a better job."
With Santos out, league sources told NFL Media the Titans are expected to sign former Chicago Bears kicker Cody Parkey. The team is flying Parkey, who worked out for Tennessee last month, in Monday night and he is expected to sign Tuesday.
It will mark Parkey's first shot at redemption after the Bears released him during the off-season following his "double doink" miss in the playoffs.
The Titans also waived offensive lineman David Quessenberry on Monday, according to the team.