Whale came on at first-five during the first half in Christchurch for Ruapehu's Craig Clare in what was reported as a blood bin, but he stayed there for the duration.
Flanker Campbell Hart was already out of the Canterbury match with a groin strain, while hooker Roman Tutauha had to gut out a bruised thigh when he came on in the final quarter.
As Taihape must take the bye in the final round-robin weekend, while Ruapehu will face Taihape and Marist on consecutive weekends, whomever slips now could have great difficulty scraping up enough points to be in the Top 4 come July 22.
Taihape won the first round match in a mild surprise as they rebounded from a shock loss to Settler's Honey Ngamatapouri to come from behind and upend Ruapehu 30-24 on April 22.
Having the bye next weekend, Black Bull Liquor Pirates are in must-win mode for the rest of the season if they are to lift from fifth spot, while Wanganui Car Centre Kaierau have nothing to lose in the cross-town derby game at Spriggens Park.
Ngamatapouri had three players in the Wanganui starting lineup on Wednesday, but with their squad filling back out they should be alright for the long trip to Taihape to meet Utiku Old Boys at Memorial Park.