Cardiff wing Adams is also unavailable this weekend, but is currently not considered an injury concern for the Six Nations.
The 29-year-old missed Wales’ summer tour of Australia and three autumn defeats against Fiji, Australia and South Africa.
Adams scored four tries in five games during his return from a knee injury that ruled him out of action for six months but missed the Cardiff defeat at Perpignan.
“It’s just a nibble,” Sherratt said. “Josh has gone through a long period of inactivity and then he came back and played five on the bounce.
“It’s a busy Christmas period and going from wet grass pitches to the Arms Park can take a bit of a toll. He might feel a bit of pain in his back.
“If we have to push it, we can play it this week. But we don’t feel the need to do that and we need to take care of Josh as much as possible.”
Despite their injury concerns, Sherratt says he is delighted the pair are part of the eight Cardiff players in the Wales squad.
“We are delighted for Josh and Tullop,” added Sherratt.
“The pair of them have worked really hard to come back from injury so to have them back is a huge boost for us, for them and for Wales.”