NPD Group published data showing that physical sales of Call of Duty: Infinite Warfare dropped 50 percent in November relative to physical sales of last year's Call of Duty: Black Ops III from the same time period.
That steep decline in the United States falls in line with data gather from UK analyst firm Gfk Chart-Track, which reported last month that the Call of Duty franchise experienced a 48 percent year-over-year decrease in first-week sales.
An anonymous source on Wall Street told CNBC that Call of Duty unit sales were down 51 percent year-over-year.
Competitor Electronic Arts, which published Respawn's Titanfall 2 and DICE's Battlefield 1 in close proximity to Call of Duty this year in order to entice consumers to its side of the fence, noted in November that digital sales account for 30 percent of total sales.
However, a 50 percent drop in disc sales spells bad news for Activision from any angle. Shares of Activision Blizzard fell 20 percent from highs in mid-October. Brian Nowak, an analyst for Morgan Stanley, predicted a 10 percent sale decline for the Call of Duty franchise.
Depending on how digital sales of Call of Duty: Infinite Warfare shake out, Activision could join the rising chorus of publishers hand-waving away concerns over low week-one sales.
"We remind people we're building a franchise with Titanfall, so it's not about the first day of sales or the first week of sales, it's about the long run," EA CFO Blake Jorgensen said following reports that early sales of Titanfall 2 would fall way under expectations. "We'll do a lot of things with Titanfall to continue to build engagement."