The talented rookie duo will get a shot eventually, but they'll have to wait a while.
"They'll get their opportunity," Harbaugh told CSNBayArea.com. "So far, with our rookies, they haven't had the opportunity to play in games. But they are practicing and doing very well."
Jenkins, a first-round pick, suited up for the 49ers first game of the season, but hasn't been in uniform since. Receivers Michael Crabtree, Mario Manningham, Randy Moss, Kye Williams and Ted Ginn are all getting snaps ahead of Jenkins.
James, who was selected in the second round, is sitting behind a healthy stable of 49ers backs, including Frank Gore, Kendall hunter and Anthony Dixon.
San Francisco plays host to the St. Louis Rams on Sunday. kickoff is slated for 1:25 p.m. PT at Candlestick Park and the game will be televised on FOX.