But Gregor Townsend has added Glasgow Warriors hooker Johnny Matthews to his squad after George Turner fell ill.
Turner, who has emerged as Scotland’s first choice hooker in recent seasons, is not expected to fly out to Chile with the rest of the party on Sunday but should be fit enough to join up later.
Hastings and Jones were both injured playing for their clubs. Hastings hurt his hamstring in Gloucester’s thumping 54-7 win over Premiership finalists Saracens while Jones was also injured against Sarries, damaging his back problem in Harlequins’ semi-final defeat.
The pair had been recalled by Townsend after they were left out of the Scotland coach’s original Six Nations squad. Hastings was eventually drafted in midway through the championship and played briefly against Italy as a late replacement.
In the absence of Finn Russell, Hastings was expected to vie with Blair Kinghorn for the stand-off role in South America. Ross Thompson is the other recognised fly-half in the Scotland squad although Rory Hutchinson can also play at ten.
The injury to Glasgow-bound Jones leaves Townsend short of experienced cover at full-back, with Stuart Hogg – like Russell – being rested. The uncapped Ollie Smith and four-cap Damien Hoyland are the remaining full-backs in the tour squad, although Darcy Graham played at 15 against Tonga in the autumn.
“Adam Hastings and Huw Jones will miss the tour, unfortunately, but that’s it. Everyone else is ready to go,” said Steve Tandy, Scotland’s defence coach.
Asked if replacements would be summoned, he added: “Not at the minute, no.
“We’ve got backs who can play in lots of different positions. There’s young Ollie Smith as well, who has done really well for Glasgow.”
The addition of Matthews, 28, is reward for a fine season for the hooker who was Glasgow’s top try-scorer.
“He has been playing really well for Glasgow, starting some big games as well, so it’s been exciting to get him in the group,” said Tandy. “He came in on Thursday and has trained really well.”
The tour begins with an A international against Chile next Saturday and continues with a three-Test series against Argentina.