Wessels is ruled out for South Africa's fall fixtures.
Springbok prop Wessels has received a ban of nine matches for grabbing opponent Josh Murphy's genitals during the Bulls' URC victory over Connacht.
The incident occurred in the 18th minute of the close contest in Galway on Friday, with opposing player Murphy receiving a 20-minute red card after responding aggressively by striking the South African on the head area.
After the Connacht player reported the incident to the match official, the event was examined by the television match official, who concluded insufficient clear footage.
Wessels remained on the pitch until he was substituted in the later stages of the game.
Although the URC confirmed that the Irish player's 20-minute red card was withdrawn by a disciplinary panel, the Springbok was deemed to have breached the code of conduct, which declares:
"A player must not engage in actions that is against the principles of fair play. This includes touching, pulling or compressing the private areas."
Disciplinary officials concluded that the event reached the level for dismissal and justified a 12-week suspension, the minimum suspension under World Rugby rules for such an violation.
Nonetheless, Wessels' ban was shortened by three weeks because of his good conduct during the proceedings and his good record.
The forward and the Bulls have the right to challenge the decision, but currently, the ban will prevent the young player out of the Springboks' fall internationals against Japan, France, Italy and Ireland.
He will also miss the his club's URC games against Glasgow, the Emirates Lions and the Cell C Sharks, as well as Investec Champions Cup games with Bordeaux and Northampton.
The prop has won 10 caps for the Springboks and was part of their tri-nations champion squad over the summer.
The Connacht player, in contrast, is eligible to play against Munster in Saturday's inter-provincial derby after being exonerated.