Westwood though added the striker could also be fortunate enough to recover in a month's time.
"Robin looks like he has got a knee injury. He has got a little bit of ACL damage. We are not sure how much extent of damage he has done. ACL can be a full tear or a 60-70 per cent partial tear," Westwood told reporters here.
"It is just the case of right surgeon (and right treatment). He may be fortunate to get away in a month. He may be unfortunate - it could be six to nine months. So, a proper qualified surgeon has to have a real look at the injuury," he added.
Even if Bengaluru FC are without the services of Robin, Westwood said the team has plenty of fowards, including Sunil Chettri, who can cover different areas.
"We have plenty of forwards who can cover different areas. Kim (Song Yong) is a No 9, although Robin was only our tallest No 9. Len (Doungel) can play there, Sunil can play there, (CK) Vineeth can also play there. So, we have got enough," Westwood said.
"It's unfortunate to lose a key memeber of the squad. He has been playing regularly for the side and have been scoring goals, but that's football, big injuries do happen. I am sure he will come back stronger, his absence means an opportunity for someone else," he added.
