Blackadder said: "With Daryl's resignation we will now reconsider the shape of those two coaching roles [attack and defence] and some variations may result depending on the specific strengths of the candidates considered for the positions.
"While we are obviously sad to see Daryl go, we must also acknowledge that this opens up a new opportunity for the Crusaders in 2013. We are aware from the process we have been undertaking to employ a new team attack coach that there is a very high calibre of coaching talent out there, so we are confident that we will be able to build a top-class 2013 coaching team and we are excited about the season ahead.''
Blackadder's other assistant is Dave Hewett, who is forwards coach.
The Crusaders have made the play-offs every year under Blackadder's tenure, but he has yet to win a title. They came closest last year despite the disruption of the earthquakes but lost to the Reds in the Brisbane final. This year they lost to the Chiefs in a semifinal in Hamilton.
The pressure is now on Blackadder, who is not contracted past next year, to deliver.