Clermont coach Franck Azema said he was disappointed with Guildford's decision. He said the team and management had done their best to support the Kiwi player.
He hoped in leaving the club Guildford found "all the stability and support necessary to help him find the right track". "We knew that we were taking a gamble with Zac. From a sporting perspective, we were successful as he has met our expectations by playing 20 games ... unfortunately the weight of the distance and that resulting weakness are hurdles too big to overcome."
Guildford was on a flight heading home yesterday and unavailable for comment.
When asked to elaborate on Guildford's decision to leave France and address speculation his personal demons had resurfaced, his manager, Simon Porter, said: "You don't need him or me to put an end to the speculation, you could just not run the story.
"The kid is just homesick, he's not the first 26-year-old who has cut an OE short," Mr Porter told the Herald.
"He's heading back to Napier initially to spend some time with family."
NZ Rugby Players Association chief executive Rob Nichol said it appeared Guildford had removed himself from a situation where he was unhappy - before he had a chance to spiral out of control. "I think that's refreshing.
"Zac has got quite a high level of self awareness for his age. From what I gather ... this is a proactive call he has made as opposed to in the past when decisions were reactive."
Mr Nichol believed Guildford had recognised he was in a situation that could easily lead to a recurrence of his "addictions" and had decided to take control of it.
Hawkes Bay Rugby Union chief executive Mike Bishop told Radio NZ talks with Guildford had already started.
The player is likely to return to his mother Deborah's home in Napier. His brother Victor also lives in the area.
The family are close and have supported Guildford, who has struggled since his father Robert's death in 2009.
