Ryder made an awesome start to international ODI career, averaging 49 at a rapid strike rate of 91.
But his career came to a sudden halt in February when he injured himself in a bar when he broke a window while trying to get into a locked toilet during celebrations following New Zealand's home one-day series win over England.
He needed surgery to his damaged right hand and a period of rehabilitation meant he missed the tour of England.
Ryder said the incident had changed his attitude "pretty much big time".
Seamer Chris Martin has been named in the one-day squad, while fast bowler Iain O'Brien and opener Aaron Redmond will join the Black Caps for the two Test matches in Chittagong and Mirpur.
With the Champions Trophy in Pakistan postponed until 2009, New Zealand have no fixtures before the Bangladesh tour, which begins with a warm-up match on October 7.