Tests revealed that Henderson suffered a mild thumb sprain that is not expected to keep him out of the season opener against the Chicago Bears on Sept. 12, a source told ESPN's Adam Schefter.
A third-year pro, Henderson was moved into the starting role entering training camp after rising star Cam Akers tore his right Achilles tendon while working out before training camp.
Second-year pro Raymond Calais, the fourth back on the depth chart, suffered a broken foot that required surgery in last Saturday's preseason loss to the Las Vegas Raiders. On Monday, the Rams waived Calais with an injury designation. Calais was competing for a spot on special teams.
With the regular season looming, coach Sean McVay said the Rams remained in the process of figuring out whether they will go with the current running backs group or look to bring in outside help.
Henderson, along with the remainder of the Rams' starters, has not played in the preseason, leaving Jones and Funk to share carries.
"We got a little bit of time," McVay said. "Darrell is a guy that's been established and done some good things. But I was pleased with both those guys."