The 31-year-old's fitness will be a significant boost to Joe Schmidt's Ireland squad ahead of next month's RBS 6 Nations.
Ireland are due to name their Six Nations squad next week and now Best has the chance to prove his fitness to win selection. The 70-cap front-row forward broke an arm in Ireland's 24-22 defeat to New Zealand in November. Best has found fitness in seven weeks, beating expectation, to return for UIster's Heineken Cup round-five tie.
Best paid tribute to Ulster's medical staff in helping him make a quickfire return. "I knew that it was going to be a tight ask to get back for these games but it is testament to the medical team that we have here, Michael Eames the surgeon and the strength and conditioning coaches at Ulster that I am back."
"I have been fortunate that there have been no set-backs along the way and it has just been a case of trying to push on and thankfully I have come through."
Another player who will be welcomed back into his international side is the fit-again centre Mirco Bergamasco, who could play for Italy for the first time in more than a year after being included yesterday in the squad for next month's Six Nations.
Jacques Brunel, the coach, has named him in a 30-man squad for the opening two matches against champions Wales in Cardiff on February 1 and France in Paris eight days later.
Bergamasco, 30, fractured a kneecap when he last played for Italy, against Australia in Florence in November 2012.
Brunel has also brought in the Zebre fullback Giuglielmo Palazzani for the first time while Benetton Treviso winger Angelo Esposito is awaiting his first start. Palazzani's Zebre team-mate Marco Bortolami will reach 100 caps should he start either of the two games at lock.