It was announced yesterday that the Scotland international is likely to miss the remainder of the Aviva Premiership season, having suffered an ACL tear in the Wasps' 20-16 victory over Northampton Saints.
Jackson will undergo surgery on his knee in the coming days, but Young acknowledges that he now faces a difficult task of replacing the summer recruit.
"It is not easy to pick up any quality player at this time of year," he told BBC Sport. "Most quality players are already signed up and working elsewhere."
The Saints, who are currently sixth in the early league standings, face Harlequins this weekend.