Ireland hooker Rory Best has been called into the British and Irish Lions squad for the tour of Hong Kong and Australia.
The Lions turned to Best after Dylan Hartley was banned for 11 weeks after being found guilty of verbally abusing referee Wayne Barnes in the Aviva Premiership final.
A final decision on Hartley's participation in the Lions tour will be dependent on the outcome of any potential appeal.
Best, who had been appointed Ireland captain for the summer tour of north America, will link up with the Lions tomorrow ahead of their flight to Hong Kong.
The Lions play their first match against the Barbarians next Saturday and tour manager Andy Irvine said: "With uncertainty over the availability of Dylan Hartley to tour, and with the first of 10 matches only days away, we had no option but to call up the additional player.
"Despite the circumstances we should congratulate Rory, who will join the squad tomorrow and fly with us to Hong Kong.
"A final decision on whether Dylan Hartley will take any part in the tour will depend on the outcome of any potential appeal."
Northampton are understood to be waiting until they receive the full written judgement from Judge Jeff Blackett, the RFU's chief disciplinary officer, before deciding whether or not to appeal.
Hartley was sent off just before half-time in Leicester's 37-17 victory and banned after being found guilty of calling referee Barnes a "f****** cheat".
The Northampton captain had claimed after the game, via Saints director of rugby Jim Mallinder, that his comments were aimed at the Leicester hooker Tom Youngs and he pleaded not guilty.
But Hartley's argument was rejected by the three-man disciplinary panel, chaired by Blackett, who handed down the third significant suspension of a chequered career.
"We cannot get around the fact that Wayne Barnes was certain that Mr. Hartley's comments were directed at him," Blackett said.
"Wayne Barnes said that if he had had any doubt in his mind, then he would have given the player the benefit of the doubt.
"In terms of sanction, calling a referee a cheat is an attack on his integrity and contrary to the core values of rugby and therefore we have taken a serious view and provided a serious sanction."
Hartley's disciplinary record includes bans for eye-gouging (26 weeks), biting (eight weeks) and punching (two weeks).
But this one is the most costly of all because - pending any successful appeal - it rules him out of the Lions tour.
Capped 47 times for England, Hartley had spoken before the final of wanting to erase the perception that he was travelling to Australia as third-choice hooker behind Youngs and Richard Hibbard.
Two minutes before the red card incident, Barnes had admonished Hartley and warned he would take action if he felt any further comments were directed at him.
And when Barnes penalised Northampton's scrum for the sixth time in the first half, Hartley reacted and became the first player to be sent off in a Premiership final.