Saracens and Scotland wing Maitland, a veteran of 48 Tests, was among the players from the invitational Barbarians whose unauthorised trip to a restaurant breached efforts to maintain a hygiene bubble, with officials subsequently calling off last Monday's (AEDT) match at Twickenham.
In March, Maitland scored two tries as Scotland ended title-chasing France's hopes of a Grand Slam with a shock 28-17 win at Murrayfield.
But Scotland coach Gregor Townsend, in a Scottish Rugby statement issued Monday, confirmed the 32-year-old Maitland's absence from this weekend's trip to Llanelli.
"We are working hard to ensure our training camp remains secure in terms of Covid protocols and, as such, Sean's actions last week with the Barbarians mean that he won't be able to rejoin our group now and we will review the situation in the coming weeks," he said.
Glasgow wing Ratu Tagive has now joined up with the squad as have the Exeter trio of Stuart Hogg, Jonny Gray and Sam Skinner fresh from helping the Chiefs win the English Premiership final a week after its European Champions Cup triumph.
Scotland, currently fourth in the standings, is aiming for its first win in Wales since 2002.
The behind closed doors game has been moved to Llanelli's Parc Y Scarlets after the pandemic saw Cardiff's Principality Stadium commissioned as a field hospital by the Welsh government.