NEW YORK – For the first time in league history, Major League Soccer implemented a rule that allows loans between its clubs, and it has been quietly in place since the start of the 2013 season.

The existence of the trading mechanism since the league began in 1996 meant that loans were initially deemed unnecessary within the MLS structure.

But times have changed. With the proliferation of MLS academies, the expansion of rosters and increased squad depth – especially signing more accomplished and talented young players – means there’s more flexibility. And now, more opportunities for these young players.

READ: Recap of MLS players loaned to lower division teams

“The loan rule is to get young people moving more in the league, especially if they are not playing for their team,” said Lino DiCuollo, MLS vice president of player relations and competition. “Teams can now execute transactions involving loans, without having to permanently relinquish a player’s rights.”

Your team has a seizure at the left-back? Now he can set up a trade involving the loan of a young left-back who straddles the pin on another MLS team. The terms of this trade, which may include other hand swap considerations in addition to the loan, are negotiated between the teams and approved by the league.

SEE: Team-by-team transactions in 2013

But there are a few basic guidelines that govern lending, as DiCuollo explains:

I) Only players 24 years of age or younger are eligible for loans;
II) Loans must be executed within the primary transfer window of a given MLS season (February 12 – May 6, 2013);
III) All loans run until the end of the MLS season (the player does not return to his home club until after the MLS Cup);
IV) The slot and budgetary considerations surrounding the loan are subject to negotiation between the two clubs;
V) There are no limits on the number of loans involving the same team (incoming or outgoing loans).

We’ll see which player goes down in history and becomes the first intra-league lender.

Time is running out, however. If this is to happen, there are only 18 days left until the main transfer window closes.