MEP Brian Crowley will address his political future at a press conference this Thursday.
The poll-topping Ireland South MEP, 54, has not attended the European Parliament since the last election due to poor health.
At that election, he ran as a Fianna Fáil candidate, topping the poll for the fifth time in a row.
However, he lost the party whip almost immediately when he registered with the European Conservatives and Reformists grouping, instead of Fianna Fáil's official grouping, the ALDE.
Soon after, he was hospitalised due to ill health and has been unable to attend parliament.
He had previously spent much of 2011-13 out of the public eye being treated for sores on his legs but was well enough to return to work and run for re-election in 2014.
At age 16, he fell from a building and was paralysed from the waist down and has been a wheelchair user ever since.
Mr Crowley was appointed the Seanad by Albert Reynolds in 1992, and was successfully elected to the European Parliament on his first run in 1994, topping the poll and taking the first seat.
He was subsequently elected at four elections, coming out with more than 180,000 votes in 2014.
Should Mr Crowley decide not to run, Fianna Fáil is likely to field at least two new candidates in the vast constituency, which now includes all of Munster and several counties in Leinster.
Former County Mayor Seamus McGrath indicated before Christmas that he is considering a run, as did Wexford councillor Malcolm Byrne.