Koo didn't travel with the team to Minnesota and won't play in Sunday's game versus the Vikings, Tori McElhaney of the Falcons' official site reports.
Parker Romo -- who was elevated from the practice squad Saturday -- will take over as the Falcons' kicker for at least one game, though it wouldn't be surprising if he permanently usurps Koo on the depth chart with a strong showing in Minnesota. Koo will end up ceding kicking duties to Romo in Week 2 after missing a 44-yard field-goal attempt late in the fourth quarter of last Sunday's 23-20 loss to the Buccaneers. His struggles date back to last season, when he connected on just 73.5 percent of his field-goal tries after hitting at least 86 percent in each of the previous five seasons.