The club from the small southern town 96 kilometres from Sofia owes over 400 levs ($277,400) in unpaid player and staff wages, taxes and other debts, club officials have said.
Some fans have even offered to donate their blood to raise cash for the club and as a way of highlighting their plight.
Under league rules, clubs with such debts will not be licensed to play in the league. Pirin have a licence for this season but may well not get one for next.
"I can't tell you anything at the moment," the Bulgarian Football Union's licensing committee chairman Krasin Krustev told Reuters.
"But if they fail to meet licensing criteria - paying their debts to the National Social Security Institute, to other clubs, unpaid wages until March 31, which is the deadline, they face expulsion.
"That's the rule. If that happens, they'll continue playing in the amateur third division," he added.
'A SHAME'
"It's a shame," Ivan Berbatov, the father of the Red Devils' in-form striker, told Reuters on Monday. "We still have the best youth academy in the country and look what's happening with our first team.
"But this is the reality," added Ivan Berbatov, also a former Pirin player. "You can't expect to survive in professional football without money.
"Isn't it pathetic? Pirin still produce top-class young players but they all go and play for other teams."
One of those was Dimitar Berbatov, who was born in Blagoevgrad nearly 30 years ago, and began as a youngster at Pirin in 1991 before leaving for CSKA Sofia seven years later.
Fans have even offered to donate their blood for money - patients in Bulgaria in need of transfusions must pay for donated blood - to raise funds for their club which appeared in European club competitions in the 1980s and 1990s.
"We're appealing for people who will use our blood to present donations to our club," said former Pirin goalkeeper Miroslav Mitev who first thought of the extraordinary way to raise money for Pirin.
Dozens of fans have so far offered to donate blood, Mitev said.
He also hoped the offer would attract attention from the local authority that some fans have accused of being indifferent to Pirin's problems.
"We're paying the price for the lack of good managers and healthy sponsors, Pirin press officer Velislav Elezov said. "Wherever we go, they say how talented our players are.
"On Saturday, we beat Europa League hopefuls Lokomotiv Plovdiv 3-1 in a pre-season friendly and a 15-year-old lad scored a goal.
"But we became a laughing stock and we still don't know whether we will play in the first division next season," Elezov said.
Pirin are 14th in the 16-team Bulgarian league with 11 points from 15 matches at the mid-season break.
Two members of the Bulgarian team that reached the semi-finals at the 1994 World Cup in the U.S. were
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