Wessels is ruled out for the Springboks' upcoming test matches.
Springbok front-rower Wessels has been suspended of nine games for making contact with Josh Murphy's genitals during the Blue Bulls' United Rugby Championship victory over the Irish province.
The altercation took place in the early stages of the close contest in Galway on Friday, with opposing player Josh Murphy receiving a temporary dismissal after responding aggressively by striking Wessels on the head area.
Following Murphy reported the incident to the match official, the situation was examined by the TMO, who concluded no conclusive video evidence.
Wessels remained on the pitch until he was substituted in the second half of the match.
Although the United Rugby Championship announced that Murphy's temporary sending-off was overturned by a governing body, the Springbok was deemed to have violated law 9.27, which declares:
"A player should not engage in actions that is contrary to the principles of fair play. Such behavior covers touching, twisting or squeezing the private areas."
The panel concluded that the contact reached the red card threshold and warranted a 12-week suspension, the minimum suspension under World Rugby rules for such an infringement.
Nonetheless, Wessels' ban was shortened by three weeks because of his good conduct prior to and at the hearing and his clean disciplinary history.
The forward and the Bulls are entitled to appeal, but currently, the suspension will rule the young player out of the South African national team's autumn Tests against the Brave Blossoms, Les Bleus, the Azzurri and the Irish team.
Wessels will also miss the Bulls' URC games against Warriors, the Lions and the Cell C Sharks, as well as European cup fixtures with Bègles and Saints.
Wessels has earned ten international appearances for South Africa and was part of their tri-nations champion squad during the recent tournament.
The Connacht player, in contrast, is available to face the Irish rivals in Saturday's inter-provincial derby after being cleared.