Edinburgh are unbeaten after three rounds, but head to Leeds this weekend knowing they may have lost the services of their influential backrower.
Blackadder admits that he fears his playing days are over.
'I'm worried that it's the end of my career,' the 32-year-old said before seeing a surgeon about the shoulder injury that has dogged him for months.
Blackadder had been hopeful of playing on to the end of the season, when he had always planned to quit, but the injury flared up again last month.
'I got some physio on it after the Celtic Cup final but, against Glasgow the following week, I felt something when I took the ball up,' he said.
'I played on but it just got sorer and sorer after the game. I couldn't have played against Leeds last week.'
Edinburgh management have been giving Blackadder every chance to make a recovery but they have already announced that fellow Kiwi Brendan Laney will again lead the side this weekend.
The club have confirmed that Blackadder underwent surgery on his shoulder yesterday on Wednesday 14th January. His injury was to the same shoulder that had surgery at the end of last season; however the two injuries are unrelated.
Gordon MacKay, the surgeon who operated on Todd, is pleased with how the operation went yesterday. He confirmed that Todd's previous injury has held up well and he will return for a follow up visit next week.
Jim McKenzie, chief executive Edinburgh Rugby, commented; "Todd's operation was a success from which he is recovering well. He will begin course of gentle rehabilitation physiotherapy in a few days time."