The Chelsea striker will soon begin his rehabilitation programme after suffering the injury in a 1-0 friendly defeat by Aston Villa in Abu Dhabi on Sunday.
The 21-year-old was left in distress in the 22nd minute of the match after getting his boot stuck in the turf and twisting his knee while closing down defender Ezri Konsa.
An anterior cruciate ligament injury will leave the Albania international with a minimum of five months on the sidelines but it could be a maximum of 12 in the worst-case scenario.
It would leave him struggling to play any further part this season as Graham Potter attempts to revive Chelsea’s poor form after the World Cup break, following a run of four defeats in their last five matches.
Broja’s injury could tempt the free-spending Blues into the transfer market in January, with RB Leipzig forward Christopher Nkunku’s move to Stamford Bridge already said to have been formalised ahead of the summer.
They may need a temporary option to fill the gap in the short-term with Atletico Madrid’s Joao Felix possibly available on a loan deal with an option to buy and former target Cristiano Ronaldo available as a free agent.