The Staffordshire-based outfit were relegated from the Premier League, despite Shaqiri contributing eight goals and seven assists from his 36 outings in the top flight.
However, when being quizzed over whether Shaqiri was one of the star players who underperformed for the Potters during the most recent campaign, Adam claimed that the Switzerland international did not produce what was expected of him.
The Scot told talkSPORT: "Was he one of them? Oh, definitely. When the chips are down you look at your big players, you want your big players to bring magic in one moment in the season, and at times we felt like the so-called big players in the squad never turned up for us and never performed.
"Yeah, everybody else could help, but for all the plaudits the so-called bigger players were getting from certain members of the management staff last season – they weren't producing."
Shaqiri has since made the switch to Liverpool.