Bradford sat out this season after tearing his ACL in a preseason game in August. He was limited to only seven games in 2013 with the same injury.
The 27-year-old is set to make $13 million in 2015 as part of a six-year, $78 million rookie contract with a reported $50 million in guaranteed money.
Over 49 career games, Bradford, 27, has completed 58.6 percent of his passes for more than 11,000 yards with 59 touchdowns and 38 interceptions.
Fisher was asked on Friday about the Rams' backup plan if Bradford were to suffer another injury.
"I don't know what that looks like right now. We'll let you know," Fisher said, according to NFL.com. "It could be a veteran, it could be a draft choice, it could be a combination of that. It could be Austin (Davis), it could be Shaun (Hill)."
Fisher was also asked about a report that Bradford recently was granted permission to seek a trade. "I was surprised to hear that -- not surprised -- but no, that's inaccurate," Fisher said. "We talked about what our plans are for him."
St. Louis went 6-10 and finished last in the NFC West last season.