The 18-year-old, who rose through the ranks at Dundee United, had been linked with a host of clubs before he sealed his switch to Portugal on a six-year contract on Wednesday.
Jackett has since conceded that he was among those to have had the midfielder scouted, but no bid was ever lodged.
"He was certainly somebody we monitored and had reports on but there was no bid and we didn't go any further than that. He was certainly in our system of players we watched," Jackett is quoted as saying by the Express & Star.
Gauld is believed to have a £48m release clause in his deal with Sporting.