Taylor, who rushed for a Bills quarterback record 76 yards in Sunday's 14-13 win over the Tennessee Titans, was "banged up" and "sore" Monday, coach Rex Ryan said. He did not elaborate on any specific injury.
"You ought to see him," Ryan said. "He is sore, and we knew he would be."
NFL.com is reporting, however, that Taylor has an MCL injury and that he will miss Sunday's game against the Bengals, meaning the Bills would almost certainly turn to EJ Manuel as their starting quarterback.
Johnson, 29, was released Monday by the Indianapolis Colts after two stints with the team this season. Johnson was a fallback option in two games in case Andrew Luck and Matt Hasselbeck were unavailable to play.
Taylor stayed on the ground following a 24-yard scramble on third-and-23 in the fourth quarter of Sunday's game, a play in which Titans linebacker Zach Brown was penalized for a horse-collar tackle on Taylor.
An official could be heard over the public address system telling Taylor to stay on the ground, but the Bills quarterback stood up and limped back to the huddle. Officials then directed Taylor to the sideline for one play before Taylor returned to the game.
Taylor then led the Bills down the field, catching a 2-yard pass from receiver Chris Hogan and taking a hard hit in his leg from Titans cornerback Perrish Cox before throwing to Hogan for the go-ahead touchdown.
It's not the first time Taylor has been injured this season.
"Guys, he hasn't been 100 percent all season," Ryan said Monday. "He's had an ankle [injury] ... even through training camp. We really haven't seen the 100 percent Tyrod Taylor."
The Bills did not list Taylor on their injury report until Week 3, when he was a full participant in practice with a chest injury. Taylor then appeared to hurt his ankle in a Week 3 win over the Miami Dolphins -- although he never missed a play -- and was listed as a full participant in practice in Week 4 with an ankle injury.
Taylor was removed from the Bills' injury report last week.