"Smaller teams than United are turning to such lenders after banks retreated from soccer following the 2007 financial crisis"
"“The vast majority of clubs just don’t have the money to pay up front,” Blake said."
"He said clubs often seek funds before the start of the season to help manage uncertainties in their cash flow, which can vary depending on the team’s performance."
Some relevant quotes from the article.
When your short-term Accounts Payable > than your short term Accounts Receivable, and your long-term Accounts Receivable > than your long-term Accounts Payable, you take out a loan to meet your expenses.
Not sure it could be any simpler