Weeknight games in the spring can be tough on ticket sales for the Portland Sea Dogs, what with school and with weather that’s often damp and cool.

But on Tuesday, there will be more fans than typical at Hadlock Field. The first 1,000 to arrive will head to their seats with a ticket in one hand and a free bobblehead doll in the other.

It’s Jackie Bradley Jr. Bobblehead Night.

“Ticket sales are running about 500 tickets ahead of other comparable April/May weekday games,” said Sea Dogs assistant general manager Chris Cameron.

But this is no ordinary bobblehead. The Bradley doll can be connected to a pair of dolls that will be given away later – Mookie Betts (June 6) and Andrew Benintendi (July 17).

Put them together and you have Win-Dance-Repeat, the celebratory dance that the Boston Red Sox outfielders do after a Red Sox win.

It’s a dance copied by kids across New England, and now it’s being immortalized in plastic, with heads attached by a spring.

For the last 15 years, the Sea Dogs have joined other minor league teams, and some in the majors, who give away bobbleheads as a way to attract more fans.

When the Sea Dogs sent out a picture of the three bobbleheads together on Twitter earlier this month, word spread fast.

“We had 57,000 impressions (the number of people who saw the original tweet) and 101 retweets,” Cameron said. “That’s one of the highest, if not the highest totals we had.

“And it looks like we sold 100 additional tickets after the social media posts.”

The Sea Dogs’ average attendance after 15 home dates this spring is 3,933, ranking fifth among the 12 teams in the Eastern League. Attendance increase during the summer; the Sea Dogs have averaged more than 5,000 fans every season.

Requests are coming in for the Win-Dance-Repeat dolls. People called wanting to know how to get a set without being at the game (won’t happen).

The Red Sox called, wanting a set. Another request came from the National Bobblehead Hall of Fame.

Yes, there is such an entity.

“At last count, we have about 7,000 unique (bobbleheads),” said Phil Sklar, co-founder of the Hall of Fame, which plans to move into a permanent home later this year in Milwaukee.

Sklar walked away from a career as corporate analyst to start the Hall. He jokes that he needed to “because my collection was growing out of control, piling up in the condo kitchen.”

Sklar and co-founder Brad Novak also create bobbleheads, which is one way they fund the Hall.

The Hall receives donated dolls – an estate just sent over 1,500 dolls – and Sklar and Novak also reach out for special ones, like the Sea Dogs set, or the one being given away at Wrigley Field this week. It features Kris Bryant and Anthony Rizzo celebrating the World Series title – called “The Final Out” bobblehead.

The Boston Red Sox recently began giving away bobbleheads, including Mookie Betts and Rick Porcello dolls already this year. Last season, one bobblehead featured David Price and his dog, Astro.

That Price-and-pooch doll can be found at Don’s Sports Card Shop in Portland, which collects and sells memorabilia. The Price bobblehead sells for $25.

“They do have a secondary value,” said Paul Kane, owner of Don’s. “They all eventually sell, even the unknowns, especially around Christmas.”

Like any collectable items, prices for sports bobbleheads can skyrocket. Go on eBay, and you will find a Derek Jeter doll, holding a World Series trophy, for $1,200. A collection of all St. Louis Cardinals bobbleheads from 2001 to 2015 is listed for $3,500.

Who knows what the full Win-Dance-Repeat set will be worth?

Cameron, when pushed, admitted that the three-outfielder bobblehead set was his idea.

“They were all (former) Sea Dogs and I thought it would be cool if we could get them to connect,” Cameron said.

It takes months for a bobblehead to be planned and created. Teams need to begin planning bobbleheads as soon as the previous season is over.

“We announce in the fall when the bobblehead dates are,” said Sea Dogs General Manager Geoff Iacuessa. “The first day of ticket sales, we have people who just want the bobblehead games. It doesn’t matter who is on them.”

While the Sea Dogs usually pick a Red Sox player who once was in Portland, players move around. The Sea Dogs already committed to a Yoan Moncada bobblehead (Aug. 15), before he was traded to the White Sox.

The team also gives away nonbaseball bobbleheads, like a Margaret Chase Smith bobblehead (Aug. 26.), honoring the former U.S. senator from Maine.

The Sea Dogs contracted Novel T-Shirts Sports Promotions of Pennsylvania for this year’s bobbleheads. The company began as a shirt company in 1975 and, in 2001, expanded its product line to include bobbleheads. Company founder Dave Meyer brought bobbleheads to the winter baseball meetings that year to display at his booth.

Usually “at those meetings, people just stop by, do some shopping. That year (with the bobbleheads), we had lines of people,” Meyer said.

Now, most baseball franchise appear to have caught the fever, including every team in the Eastern League. The Sea Dogs’ first bobblehead was a Josh Beckett model in 2002.

Portland’s most popular offering may have been a Babe Ruth bobblehead, although more recent Red Sox bobbleheads have attracted crowds.

Jacoby Ellsbury was once a celebrated Red Sox player and, when his bobblehead was given away at Hadlock Field, the line stretched down the street to the Expo.

Fans usually begin lining up at Hadlock before the gates open because only the first 1,000 fans receive a bobblehead. Iacuessa emphasized that fans receive only one bobblehead, no matter how many tickets they have.

Because Tuesday’s schedule has been changed to a doubleheader, the first game will start at 5 p.m. Gates will open at 3:30 p.m.

Kevin Thomas can be reached at 791-6411 or:

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Twitter: ClearTheBases