Weir, the 27-year-old stand-off discarded by Edinburgh in the summer, is now undergoing pre-season training with new club Worcester Warriors ahead of the 2018-19 campaign.
He has not given up hope of returning from the international wilderness to play for Scotland at the 2019 Rugby World Cup in Japan, but has revealed just how bad things got for him during 2017-18 while he was with Edinburgh.
“I started the first few matches of the season, then I was battling along with a groin injury that got progressively worse,” said the 27-times capped player.
“Being quite stubborn I tried to keep training and playing, but it came at a cost and I eventually agreed to have a steroid injection.
“It should have been a routine six-week lay-off, but instead I picked up a bacterial infection from the injection that spread right through my pelvis and pretty much wasted away the lower half of my body.
“I was on crutches and could barely move out of bed.
“Eventually we worked out treatment and it ended up a four-month lay-off.”
Now he hopes his move to Worcester can put him back into Gregor Townsend’s plans with a whole host of Test matches to come in the next 12 months.
“It is absolutely my ambition to get back involved with Scotland,” the former Glasgow and Edinburgh man said.
“Gregor gave me a really positive phone call at the end of last season and said that he was enjoying seeing me back playing.
“It is going to be a huge year for Scotland in 2019 and if I can make another World Cup that would be brilliant.”