Iain Henderson has escaped suspension and will be available to play for Ireland in Sunday's Six Nations game against Italy in Rome.
The Ulster lock was cited for dangerous play for a tackle during Saturday's Pro14 win over the Ospreys in Bridgend.
A disciplinary panel agreed on Tuesday an act of foul play did happen, but that it merited a yellow card only.
Fit-again Henderson, who gave evidence via video link, should now play in his first Six Nations game of the year.
Henderson was involved in an attempted clear-out of a ruck but had a penalty awarded against him for the challenge on Ospreys flanker Sam Cross.
The second row was reported for alleged infringement of Law 9.11 - players must not do anything that is dangerous to others - which carries a minimum sanction of a two-week ban.
The panel did not uphold the citing complaint "given the limited ability of the player to take avoiding action in a short space of time".
As the act did not merit an on-field red card, the citing complaint was not upheld.
"The player is free to play," said a statement from the panel.
Henderson was named in the 34-man Ireland squad on Tuesday after missing the first two Six Nations games through injury.
Tadhg Beirne is fit for the first time in this year's tournament and provides another option in the second row.
Centre Chris Farrell has shaken off injury concerns, after damaging his knee in Munster's weekend win over the Southern Kings, but fit-again Connacht scrum half Kieran Marmion has been overlooked.
His uncapped Connacht team-mate Caolin Blade instead keeps his place as cover for Conor Murray and John Cooney.
As expected. Garry Ringrose and Rhys Ruddock are ruled out with hamstring injuries while lower back stiffness has robbed Ulster utility back Will Addison of the opportunity to impress the coaches.
Ireland squad (v Italy): Forwards - Best (capt), Beirne, Conan, Cronin, Dillane, Furlong, Healy, Henderson, Kilcoyne, J McGrath, Murphy, O'Brien, O'Mahony, Roux, James Ryan, John Ryan, Scannell, van der Flier; Backs - Aki, Blade, Byrne, Carbery, Carty, Conway, Cooney, Earls, Chris Farrell, Tom Farrell, Henshaw, Kearney, Larmour, Murray, Sexton, Stockdale.