HAWTHORN star Jarryd Roughead is still unsure about what forced him to require a PCL reconstruction, with the key forward set to go under the knife tomorrow.

The four-time premiership player had been managing his injury and even managed to play the International Rules Series Test in Ireland but the situation worsened after Christmas.

"I hurt it last year in a game against Carlton (in round 17)," Roughead said on Monday on Gold FM.

"I had the scan at the end of the year to see if I could still go on the International Rules trip, which came up fine.

"I did all the training over Christmas, then came back, and for some reason, I don't know what, the knee started to flare up."

Roughead, a two-time All Australian, is set to miss the first half of the season.

He said there was the option of a clean up with a quicker recovery time, but that could have resulted in reinjuring his knee.

"It's a 16 to 20-week injury, (but a reconstruction) could prolong your career."

To make matters worse, Roughead found out he would be missing a large chunk of the season the day before his wedding.

Roughead also expressed his surprise at hearing of president Andrew Newbold's resignation from the role.

"When I heard the news I was very shocked. He's done a great job and left the club in wonderful hands."

Newbold has been replaced by Richard Garvey, who was previously vice-president of the club.