YARMOUTH — Although he was born and raised in Maine, Joey Morrill is, at heart, a new jersey boy.

Actually, he’s more of a used jersey boy.

Morrill, 21, collects baseball jerseys the way some kids collect baseball cards. Over the past six years, he has accumulated more than 100 jerseys worn by members of the Portland Sea Dogs.

He has home jerseys. He has road jerseys. He has batting practice tops. Some are trimmed in teal from Portland’s days as a Marlins affiliate. Most have the red or navy blue of the current parent club, the Boston Red Sox.

If ever you played or coached for the Sea Dogs, chances are Morrill has your number.

“It’s almost like a hunt,” Morrill said, “to see which one you can get next.”

Joe Morrill in the room holding collected Sea Dogs jerseys and memorabilia in Yarmouth. Whitney Hayward/Staff Photographer

Joe Morrill in the room holding collected Sea Dogs jerseys and memorabilia in Yarmouth. Whitney Hayward/Staff Photographer

A senior chemistry major at the University of Southern Maine, Morrill recently purchased his 113th Sea Dogs jersey, all of them neatly on display in the bedroom of his 15-year-old brother, Dom, either on a wall or hanging from a specially built double rack.

By living at home throughout college and working at a science laboratory in Portland (full time in summer and 20 hours a week during the school year), Morrill can support a habit that he figures has cost him north of $4,500.

He paid $10 apiece for some of his least expensive jerseys – ones without names on the back – purchased at what the Sea Dogs bill as their annual yard sale. The most Morrill ever paid was $335 for a road jersey worn by Mookie Betts, who now patrols center field for the Red Sox.

A 2012 study done by SportsMemorabilia.com estimated the market for licensed sports merchandise to be about $12 billion, with jerseys making up roughly a quarter of that. The autographed market, according to the study, is pegged at $1.5 billion.

Although he hopes his jerseys rise in value, Morrill doesn’t view them as investments. It’s been a few years since he sold any, and even then he did so only to be able to buy more of them.

Morrill played ice hockey at Yarmouth High and started collecting when he was about Dom’s age. Three years ago, his family bought three season tickets to Hadlock Field and he began collecting in earnest.

“He works and buys all this stuff himself,” said his dad, Jim Morrill.

Many of Joey’s friends think his hobby is crazy.

“They try to tell me what they would spend the money on,” he said, “which isn’t Sea Dogs jerseys.”

Dom is on his side, however, and watches over the collection as if it were behind a glass case in Cooperstown. Joey’s favorite jerseys hang from Dom’s bedroom walls. Four No. 7 Sea Dogs jerseys – worn by Betts, Xander Bogaerts, Jackie Bradley Jr. and Garin Cecchini – are prominently displayed.

Other high-profile wall-hangers are outfielder Rusney Castillo (18), catcher Christian Vazquez (33) and pitchers Henry Owens (39), Brian Johnson (38) and Eduardo Rodriguez (23 in a “Star Wars” motif).

It doesn’t stop with jerseys. Morrill also has 40 pairs of baseball pants, dozens of cracked bats, 37 bobblehead figurines arranged on four shelves, 20 game-used hats and lineup cards that once hung inside Portland’s dugout.

A large framed poster of the original 1994 Sea Dogs hangs high on one wall.

“I think we bought that one at a flea market,” Morrill said. “That’s one of our better finds.”

Of course, the only face he finds familiar in that photo – taken the year he was born – is that of team senior vice president John Kameisha. He’s the guy who unloads excess Sea Dogs inventory either in online auctions, special sale tables in the team’s souvenir store or at its annual yard sale.

Kameisha said nobody comes close to Morrill when it comes to collecting jerseys. When a longtime season-ticket holder who had collected a trove of Sea Dogs merchandise was downsizing and looking to sell her collection, she asked Kameisha if he knew anyone who might want her stuff.

“I think I might,” he replied.

Last month the Morrill brothers traveled to Pawtucket, Rhode Island, home of Boston’s Triple-A ballclub, in hopes of getting some of his jerseys signed by the former Sea Dogs who wore them. In the parking lot after the game, Cecchini, who had recently returned to the minors after two days with Boston, did not pause for a cluster of autograph seekers as he walked to his car.

As the car was pulling out, Morrill silently held up a white Sea Dogs jersey with a red numeral 7 on the back, just below an arch of block letters that spelled CECCHINI.

Cecchini stopped the car, motioned Morrill over and scribbled his name across the top of the jersey’s No. 7 before continuing on his way.

“We were the only ones he signed for,” Morrill said.

Now that the Sea Dogs’ season is over, Morrill is turning his attention to hockey. He has 67 Portland Pirates jerseys in his closet, and the team recently unveiled a new uniform design.

“I do wear normal clothes,” Morrill said. “But we wear (the jerseys) to all the games and in winter to make baseball season come earlier.”

Don Morrill sits in the room holding collected Sea Dogs jerseys in Yarmouth. Whitney Hayward/Staff Photographer

Don Morrill sits in the room holding collected Sea Dogs jerseys in Yarmouth. Whitney Hayward/Staff Photographer