He has been ruled out of action for around six weeks after going under the knife and will now miss the start of the season unfortunately.
When you are his age, it can take you longer to get back up to speed again.
It is a real blow to Jon but the good thing from Ally McCoist's point of view is that he has added Kris Boyd and Kenny Miller to the squad this summer so he isn't short of options up front.
Calum Gallacher came in last season and did well and you can't forget Dean Shiels and David Templeton.
It is never ideal being injured and, if Rangers get off to a good start this season, big Jon might find it hard to get himself back into the team.
If the front two of Boyd and Miller are scoring goals, I can't see how he will get back in to the side when he is back fit and available again.
He will miss the four game tour of North America that Rangers fly out for this weekend and that will be an important time for the squad.
People are saying the club is skint and are asking how we can afford to go to America and Canada.
It is all paid for, though. It is all sponsored. So Rangers don't need to pay for it.
It is good to get away and play in different countries and against different teams.
All the players will get a game over the four matches.
It is important to be away together and it will really help the younger lads especially.
All they will do is eat, sleep and talk football so I think the tour is great.