Premier League's Chelsea on Friday have filed an appeal against the two-window transfer ban imposed on the club by FIFA at the Court of Arbitration for Sport (CAS).

"The Court of Arbitration for Sport (CAS) has registered an appeal filed by Chelsea Football Club Ltd (CFC) against the Federation Internationale de Football Association (FIFA)," said the CAS in a statement.

In February, the world soccer governing body decided to punish Chelsea for breaching FIFA rules of signing international players and registering for U18 players by forbidding the English club from registering anyone in the future two transfer windows, specifically this summer and January 2020.

In April, Chelsea took the ban to FIFA, hoping that it could be partially lifted so they could at least introduce U16 players who are not "international transfers and first registrations of foreign players. However, FIFA turned down Chelsea's request, which then decided to turn to the CAS for help.

One of the reasons why Chelsea are eager to have the transfer ban lifted or suspended was that they did not want to fall behind in the arms race in the European soccer world, especially when they sent Eden Hazard to Real Madrid for reportedly over 100 million pounds (about 127 million U.S. dollars). The club had already brought the 2018-19 UEFA Europa League trophy to the Stamford Bridge and secured a spot in next season's UEFA Champions League, so they had to keep investing to stay among Europe's top clubs.

However, so far there is no confirmed timetable for the CAS' hearing of the case, which means there's a very good chance that Chelsea may have to sit through the 2019 summer without making any improvement on their franchise.