Tomorrow is the day for Activision Blizzard (Nasdaq: ATVI) investors to mark on the calendar, as the company's fourth-quarter earnings are set to be released after the closing bell. What kind of digits can shareholders look forward to?

Looking at consensus estimates, analysts are expecting revenue in the fourth quarter to come in at $2.2 billion, which would be a 14% fall from the prior year's $2.55 billion in sales. The bottom line is expected to improve to $0.56 in earnings per share, a notch higher than the $0.53 per share profit a year ago.

The headline numbers won't tell the whole story, especially considering that Activision put up a beat last quarter but still sold off over concerns about one of its biggest cash cows, World of Warcraft, losing 800,000 subscribers, or 7% of its player base, during the third quarter. All eyes will likely be on WoW's performance, especially since rival Electronic Arts (Nasdaq: EA) just released its own Star Wars: The Old Republic over the holidays, a competing massively multiplayer online role-playing game, or MMORPG.

EA ended up topping estimates when it reported last week, and it also mentioned that The Old Republic sold 2 million copies in its first month, growing its active subscriber base up to 1.7 million. The game comes with a free 30-day trial, so we'll have to wait to see how those figures withstand the test of time.

Looking at fellow game makers' results, Take-Two Interactive (Nasdaq: TTWO) reported last week to little fanfare, with Max Payne 3's painful delay weighing on results while everyone is still waiting for a release date of the next installment of its blockbuster franchise, Grand Theft Auto.

Activision has been embracing mobile gaming platforms, but online subscriptions and consoles are still the lion's share of sales. I'll be watching to see if those WoW figures can wow investors.

Don't forget to add Activision to your watchlist so you don't miss its digits tomorrow.