The drive came off the bat of Rockies outfield prospect Charlie Blackmon. The D-backs pulled Duke from the contest almost immediately after trainers arrived to look at him. Right-hander Jarrod Parker replaced Duke.
Duke said he will be evaluated by team doctors on Sunday. Because there was no sharp pain when he was tested by athletic trainers Saturday night, Duke was optimistic the injury wasn't serious.
"It squared me up pretty good, right in the back of the hand," Duke said. "I've got a nice 'C' mark on there.".
It wasn't the first bit of bad luck for Duke. Third baseman Geoff Blum committed an error to allow Rockies leadoff hitter Dexter Fowler to reach in the first inning. Fowler scored on Todd Helton's single to tie the score at 1. Chris Iannetta, the batter before Blackmon, reached on another Blum error.
Duke had given up three solo home runs in his previous outing, a loss to the White Sox that dropped him to 0-2 with a 9.00 ERA in three Cactus League appearances. Before joining the D-backs this year, Duke was the winningest pitcher in the history of PNC Park, going 31-31 in 81 starts for the Pirates.
Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, and follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.