Murphy last appeared in a game Friday, when he injured his right shin on an aggressive slide at first base.
Davis (right calf) and Duda (left hamstring) each last played early last week. Davis again was spotted Tuesday morning navigating the clubhouse in a walking boot.
Duda has seemed the closer of the first basemen to returning.
“They did stuff inside today, some movement drills -- both he and Ike,” Collins said after Tuesday’s 9-8 win against the Cardinals in Jupiter. “We’re hoping that they do it again tomorrow. And then we’re hoping on Thursday maybe at least get them into minor-league camp and DH them.”