The 27-year-old spent two nights at the Royal Liverpool Hospital but has now returned home to begin his recovery from the injury, which he suffered in an innocuous-looking clash with Raheem Sterling in Wigan's 3-0 defeat by Liverpool on Saturday.
Watson will need to wear a cast for a few weeks but the club are optimistic he will be able to resume training in the new year.
The midfielder has been in and out of the side this season but had started the last three Premier League games and he will be missed, according to manager Roberto Martinez.
The Spaniard told the club's official website: "It's not as bad as it could have been, that's for certain. It's still a very serious injury and we need to ensure that Ben is given all the time that he needs to make a full recovery.
"The good news is that he won't be out for as long as we initially thought and, with the character that Ben has, he will be able to deal with such an injury.
"Ben has just started to put his stamp on the team and he will be missed in the group because of the type of lad he is."