Nicki Jhabvala of the Denver Post reported on Wednesday that Booker suffered a hairline fracture. On Thursday morning, NFL Network's Ian Rapoport reported Booker had "been lifting with it for weeks, aggravated it in training."
The Broncos selected Booker in the fourth round (No. 136 overall) of the 2016 draft. While C.J. Anderson was the presumed starter, it became clear that Booker would earn plenty of touches in his rookie campaign.
By the time the 2016 season came to a close, Booker logged 174 carries for 612 yards and four touchdowns. He also caught 31 passes for 265 yards and a score while appearing in all 16 games for the Broncos.
But now that the 25-year-old is reportedly out through training camp and possibly into the start of the regular season, Booker could fall behind in a crowded Broncos rushing rotation.
Not only is Anderson returning as the presumed starter, Denver also signed veteran Jamaal Charles as a change-of-pace option to bolster its backfield depth.
With Booker banged up, those two should be afforded every chance to operate as an effective thunder-and-lighting combination as the 2017 season approaches.