08/26/2008 at 05:00 PM EDT
Perhaps it's a case of too much baby lifting, because new dad Keith Urban
has been diagnosed with a slipped disc, his publicist, Paul Freundlich, confirms to PEOPLE.
The rep wouldn't comment on what caused the injury, but says it won't affect the singer's touring schedule.
Urban, 40, mentioned the setback to fans at a concert Saturday night at the Konocti Harbor Resort & Spa in Kelseyville, Calif., but, according to CMT.com
, he went on to deliver an enthusiastic performance.
The singer has been dividing his time between Australia – where he, wife Nicole Kidman
and their 7-week old
daughter, Sunday Rose, have been visiting family – and his North American tour dates.
Next up is a headliner slot at this weekend's Country Rocks Festival in Halifax, Nova Scotia, to be followed by a Sept. 5 appearance in New York City's Columbus Circle for the NFL's Kickoff Show.