According to raw retail data collected by NPD, consumers bought just 1,758 HD DVD players the week of January 12, down from 14,558 players the week before. In contrast, consumers bought 21,770 Blu-ray Disc machines, up from 15,257 the previous week.
However, NDP's analyst Stephen Baker said that it was too soon to tell whether this is the start of a long-term trend, according to Reuters.
"It's always very dangerous to make long-term assumptions based on one-week sales data," he said.
Baker said that while the Warner defection might have had an impact on HD DVD player sales, other factors also may have come into play, including an aggressive promotion by Sony and Sharp in which HDTVs were bundled with Blu-ray Disc players.
"One week just doesn't give us enough data points to say something is going on for the long term. It only tells me in one week something happened," Baker said.
NPD tracks point-of-sale data from major U.S. retailers that collectively account for about two-thirds of consumer electronics hardware sales.
Earlier this month, Toshiba began slashing pricing on its HD DVD players, including cutting $150 off the HD-A3 to $149.