The London club confirmed yesterday that the 26-year-old has suffered an anterior cruciate ligament tear which will require surgery. The club expect him to be sidelined for between six and nine months.
He will now bid to recover in time to be available for the 2015 Rugby World Cup next September. Jackson, who has won 25 Scotland caps, joined Wasps from Glasgow Warriors in the summer.
“We are all incredibly disappointed for Ruaridh, who has made such an impact since joining Wasps this season,” Wasps rugby director Dai Young said.
“He has impressed me during training, both with his skill level and his attitude, and it’s a real blow to lose him after he played so well in pre-season and when he came on against Northampton last Sunday.
“Our medical team will be monitoring Ruaridh carefully and supporting him through this frustrating period.
“Professional sport is cruel at times, and this is certainly one of those times.
“Alex Lozowski will now have an opportunity to impress over the next few weeks, alongside Andy Goode, while we also have the option of playing Rob Miller at fly-half.”
Jackson made his Test debut against New Zealand in 2010. His most recent international appearances were against the USA and Canada during Scotland’s summer tour three months ago.
Scotland kick off their autumn Test series against Argentina at BT Murrayfield on 8 November, then play New Zealand a week later and Samoa on 22 November.
• English Premiership Rugby chiefs have confirmed changes to the league’s salary cap from next season.
As expected, the base salary cap level will rise to £5.1million, plus £400,000 in home-grown player credits. This season’s salary cap is set at £5m.
Each Premiership club will additionally be able to nominate up to two ‘excluded players’ whose salary is not included in the cap.