Last month Bilic said signing the former Arsenal midfielder permanently this summer after a loan spell last season would show the world just how ambitious the Hammers are for the future.
"Look, we know what Alex Song is and it also shows the size of the club," Bilic told West Ham's official website.
But the former Croatia manager's best laid plans could be in jeopardy now after a report in the Mirror claimed the midfielder needs surgery on an ankle injury.
Move in doubt over injury?
According to the report Song could have to go under the knife to remove a piece of bone which has caused an ankle injury.
But the club are said to be actively aiming to rescue the deal by looking into another season-long loan deal for the former Cameroon captain.
While it remains to be seen whether the African's future will be in East London, would it make a huge difference to Bilic's plans for the season?
Song played 28 games last season and early on there was a running joke on the terraces that the Man of the Match could be named before kick-off given the number of times Song had won the award.
Injuries undoubtedly affected his form later in the season and when Sam Allardyce departed in May it seemed Song may have played his last game for the club.
Form mirrored that of his team
His form very much mirrored that of the team last season, which perhaps reflects just how influential a player he is.
Before Christmas, Song was the best player on the park most weeks and he led the Hammers to the dizzy heights of fourth by the new year.
But he was so ineffectual in 2015 many wondered if they were watching the same player, as West Ham won just three games to slip all the way down to 12th by the season's end.
If Bilic can get the best out of a player that should still have a good five or six years left at the top level then he will be a force to be reckoned with in the heart of midfield.
But should he join carrying an injury and play like he did in the second half of last season, questions will soon be asked.
One thing the Hammers can rest easy knowing is that they now have plenty of strength in depth in midfield.
They have signed the likes of Pedro Obiang, Dimitri Payet and youngster Martin Samuelsen from Manchester City who could be the surprise package of the season.