Liga MX teams last participated in the Copa Libertadores in 2016. Mario Ocampo/LatinContent/Getty Images

Liga MX clubs are unlikely to rejoin the Copa Libertadores anytime soon, with the calendar clash between Mexico's first division and CONMEBOL's club tournament still an impediment.

Mexican teams were invited to enter the Copa Libertadores in 1998 and had remained until 2016, before CONMEBOL announced a restructuring for the 2017 edition, with the competition now running from January until November.

With Liga MX's split-season format going from January until May (Clausura) and then July until early December (Apertura) and the Copa MX and CONCACAF Champions League all in the equation, Mexican clubs pulled out of the 2017 edition.

The prospect of Mexican clubs returning is possible, however Liga MX president Enrique Bonilla suggested on Monday it would only be when CONMEBOL adjusts its calendar.

"There has never been a refusal from CONMEBOL," said Bonilla, after a Liga MX owners' meeting. "Their format contrasts with the interest of the Liga MX calendar.

"The door is open for when they make a change and [the Libertadores] doesn't go against our calendar," he added.

The prospect of a cup competition involving teams from MLS and Liga MX to fill the hole of the Copa Libertadores was reportedly close last May, but Bonilla suggested the parties were still talking things over.

"We are having talks [about] a possible invitation from [MLS]," said Bonilla. "We're on track to work on a formal relationship to construct the best for both [leagues]."

The prospect of a cup competition between teams from the two leagues came up as far back as October 2015.

Gremio won the 2017 Copa Libertadores last week in Argentina, after overcoming Lanus in the final.