The injury means Howard will miss an instant clash with old club Swindon Town and could leave the winger on the sidelines for six weeks thus ruling him out of the pre-season friendlies and leaving him desperately short of match fitness.
Tykes boss Andy Ritchie said: "I am very disappointed and Brian is absolutely gutted but we have to look after his long term well being and this is the best course of action.
"We are all disappointed that Brian will not be with us for the first weeks of the season but there is no point dwelling on it now and we just have to get on with it".
Reds physio Rick Holden added: "Brian came in from training on Friday afternoon complaining of a sore right foot so we sent him up to the hospital for an x-ray.
The scan showed that unfortunately he has a small crack in the fifth metatarsal head. He went to see a consultant on Saturday morning and will now undergo an operation on Tuesday.
"The crack itself it not too bad and it is not that big but we have to make sure that it heals properly. He should be out for about six weeks, but we are very confident of a full and speedy recovery.
"On one hand we are all devastated that we will be losing a player of Brian's ability and skill for the first few weeks of the new season but I am pleased in one respect because we have caught the injury while it is still a minor crack."