Jets coach Rex Ryan controversially brought on Sanchez in the fourth quarter of a pre-season match against the New York Giants, leading to the quarterback suffering an injury that has ruled him out of the opening match of the season.
However, Johnson refused to blame Ryan for the incident and hinted that Sanchez should have taken better care of himself.
"That was a decision that was made. I don't have any regrets. He's an experienced guy. I wished he hadn't gotten hurt, but you've got to protect yourself too," Johnson told reporters.
Smith will play his first NFL match when the Jets take on the Tampa Bay Buccaneers in their opening game of the new season on Sunday.