Pause the football game and put the Thanksgiving pie on hold -- this year's holiday shopping kickoff comes earlier than ever before.

Retailers large and small will start sales around dinner time on Thanksgiving Day -- with a few offering doorbuster deals early Thursday morning -- trying to lure shoppers into stores and away from the table.

Facing the shortest holiday shopping season since 2002 -- just 26 days compared to 32 last year --- many retailers have shifted their best sales from Black Friday to Thanksgiving Day.

"They'll hit hard, hit early and be very, very early," said Tamara Gaffney, marketing manager with Adobe (ADBE) Digital Index.

The shortened holiday calendar could cost retailers $1.5 billion in sales this year, Gaffney said, because shoppers will make fewer trips to the stores and, with less time to prepare for expensive purchases, many will settle for more practical gifts. Retailers are scrambling to prevent that shortfall -- many rely on the holidays for 40 percent of their annual business.

Experts say the trend toward earlier sales is expected to continue, and in a few years, the Black Friday that consumers have known for three decades will be an outdated tradition.

"It's becoming more obsolete," said David Johnson, chief executive officer of Strategic Vision LLC, a Georgia-based branding firm. "In five years, Black Friday as we know it will be gone."

Black Friday began creeping into Thanksgiving a couple of years ago, led by Toys R Us, which announced it would open at 9 p.m., and Walmart started sales at 10 p.m. Last year, more big retailers laid claim to Thanksgiving evening and some Bay Area malls opened at midnight for the first time.

This year, Kmart announced it would open at 6 a.m. on Thanksgiving -- angering some consumers who said it was a violation of the holiday -- and stay open for 41 hours straight. Old Navy stores will also open for Thanksgiving morning, at 9 a.m., and Toys R Us opens at 5 p.m. -- three hours earlier than last year.

Walmart bumped up its Thursday opening from last year by two hours and will start doorbusters at 6 p.m., and Target opens at 8 p.m., an hour ahead of last year. Macy's and Kohl's open at 8 p.m. -- the first Thanksgiving appearance for each. Old Navy plans to close briefly Thursday before most stores reopen for Black Friday; other stores will stay open around-the-clock.

"People are past the notion of waking up at 4 in the morning (on Friday) and crawling out of bed to go shopping," said Gidi Fisher, chief executive officer of PoachIt, an online coupon service and price tracker. "It's easier to get to the store Thursday night."

Target says its Thanksgiving opening allows customers more flexibility.

"We are making it easier for guests to build a Black Friday ritual that works for them," said Target spokesman Matias Cavallin.

Even if it means forgoing a second serving of pie, shoppers will show up, experts say. Many consumers still look forward to the adrenaline rush of battling for a parking spot and arriving first in line, said Andy Werner, a retail specialist with Experian Marketing Services.

If trends continue, shopper turnout will be the strongest this year since the Thanksgiving creep began. According to the National Retail Federation, in 2010, 10 percent of shoppers were in the stores by midnight on Black Friday; in 2011, 24 percent were shopping on turkey day. Last year, 28 percent -- more than 35 million people -- shopped on Thanksgiving. The early store openings contributed to record holiday weekend spending last year -- $59 billion, about a 13 percent increase over the previous year.

"Stores are opening to millions and millions of people who want to shop off that Thanksgiving dinner," said Pam Goodfellow, a director for Prosper Insights & Analytics, which tracks national retail trends. "Retailers are only giving shoppers what they really want."

But not all shoppers are keen on the new hours.

"The more they do this and take away from the Thanksgiving holiday, the more I go to Amazon.com," said Bay Area shopper Mike Rodrigues.

This year marks the earliest opening ever for Vacaville Premium Outlets -- some stores open at 6 p.m. Thursday -- and shoppers are expected to line up long before that, said Maura Eggan, vice president of marketing. Westfield Valley Fair in Santa Clara will open most stores to shoppers at midnight, although a few retailers, including The Gap and Banana Republic, open at 8 p.m.; five years ago, mall shopping started at 7 a.m. Friday. General Manager Matt Ehrie said he expected higher shopper turnout than last year.

One person who won't be there is Brian Nelson. Outside a Sears store in Oakland on Wednesday, Nelson said he would wait.

"I will shop on Black Friday -- the actual Black Friday," he said. "Not Black Thanksgiving."

Contact Heather Somerville at 510-208-6413. Follow her at Twitter.com/heathersomervil.

Thanksgiving Day openings
Kmart 6 a.m.
Old Navy 9 a.m.
Toys R Us 5 p.m.
Best Buy 6 p.m.
Sports Authority 6 p.m.
Vacaville Premium Outlets 6 p.m. (select stores)
Walmart 6 p.m.
Dick's Sporting Goods 8 p.m.
JC Penney 8 p.m.
Kohl's 8 p.m.
Macy's 8 p.m.
Office Depot 8 p.m.
Office Max 8 p.m.
Sears 8 p.m.
Staples 8 p.m.
Stoneridge Shopping Center 8 p.m.
Sun Valley Shopping Center 8 p.m.
Target 8 p.m.
Westfield Valley Fair 8 p.m. (select stores)


Thanksgiving shopping gains popularity
Shoppers who were in the stores by midnight:
2010 --10 percent
2011 -- 24 percent
2012 -- 28 percent (more than 35 million people)

Who shops on Thanksgiving?
Millennials -- 36 percent of holiday shoppers ages 18-34 hit the stores on Thanksgiving last year

Why shop early?
-- Consumers say they want to spread out their spending, pick up hot-selling items such as the latest XBox and beat the weekend crowds

Source: National Retail Federation