Dublin (AFP) - Irish captain Caelan Doris is fit and will face France handing a massive boost to Ireland ahead of their potential Six Nations title decider in Dublin on Saturday.

The 26-year-old No 8, who missed the win over Wales last month owing to a knee injury, will win his 50th cap and is one of four changes to the starting XV from the Welsh match.

Fullback Hugo Keenan returns, as does prop Finlay Bealham, who was a replacement against the Welsh, and Bundee Aki comes in to partner Robbie Henshaw in the centres for the suspended Garry Ringrose.

“Caelan has done incredibly well to get back to full fitness,” Ireland’s interim head coach Simon Easterby told reporters on Thursday.

“It says a lot about him that he has done as many other players might not have been able to do that in such a short space of time.”

Jamie Osborne, who stood in for Keenan against Wales, moves to the wing as Mack Hansen has a thigh injury.

Easterby said Osborne’s versatility earned him the nod ahead of an out and out winger such as Calvin Nash.

“We felt it was right to give him (Osborne) the right wing as it gives us coverage across the backs due to his versatility,” said Easterby.

“Mack (Hansen) was touch and go but he was comfortable with the call.”

Sam Prendergast and Jamison Gibson-Park, who has been outstanding thusfar, will form the half-back partnership.

Jack Conan, who started the Wales game instead of the injured Doris, has also recovered from a lower back problem and will be on the bench.

Like Bealham and Doris, Conan is set for his 50th Test appearance.

- ‘Cracking contest’ -

On what will be an emotional day at Lansdowne Road three legends will be making their final home appearances.

Scrum-half Conor Murray – who formed a world class half-back partnership with Johnny Sexton for many years – Ireland’s record caps-winner with 136 Cian Healy and last year’s title winning skipper Peter O’Mahony will all retire from Test rugby after the final match at Italy next Saturday.

“This weekend gives the Irish public the chance to mark the final home international appearances for Peter, Cian and Conor -– three stalwarts of Irish rugby who help drive the highest standards in our camp,” said Easterby.

Easterby said although it would be emotional he did not think they would wish for their teammates to be motivated solely by their impending retirements.

“They leave a massive void as they have been part and parcel of international rugby for so long,” said the 49-year-old former Ireland flanker.

“As a mark of respect and motivation they and the team want to finish on a high. That’s all they have ever thought about is what is best for the team.”

The Irish are on course for an unprecedented third successive Six Nations title and are the only side capable of achieving the Grand Slam.

However, France have aspirations for the title – England could also win it – and are the last side to have won a Six Nations match in Dublin, in 2021.

Victory for the French would put them in pole position for the crown ahead of the final matches – they host Scotland and Ireland are in Italy – as their points difference is vastly better than their hosts on Saturday.

Easterby, standing in while Andy Farrell takes charge of the preparations for the British and Irish Lions tour of Australia, said it should be a “cracking” Test match.

“The team has worked hard again this week and the preparation has been positive for what we know will be a huge test against France,” said Easterby.

“There’s great respect and rivalry between the two teams and it should be a cracking contest.”

Team (15-1)

Hugo Keenan; Jamie Osborne, Robbie Henshaw, Bundee Aki, James Lowe; Sam Prendergast, Jamison Gibson-Park; Caelan Doris (capt), Josh van der Flier, Peter O’Mahony; Tadhg Beirne, Joe McCarthy; Finlay Bealham, Dan Sheehan, Andrew Porter

Replacements: Rob Herring, Cian Healy, Thomas Clarkson, James Ryan, Jack Conan, Ryan Baird, Conor Murray, Jack Crowley

Coach: Simon Easterby (IRL)