Since Brendan Rodgers resigned as Celtic manager on Monday, several candidates have emerged as the Northern Irishman's long-term successor. Celtic moved quickly to appoint former manager Martin O'Neill as interim boss - 20 years after his first stint in charge of the Glasgow club ended.

Sunday's 3-1 defeat at table-toppers Hearts was Celtic's second successive Premiership loss, leaving them eight points adrift in second place, while they have won just two of their last seven matches across all competitions. O'Neill, 73, has played down suggestions he could take up the job on a full-time basis - insisting he is just "keeping the seat warm".

Several candidates have already started to emerge for the position, including some names that have strong links to Parkhead. BBC Sport assesses the options and looks at how realistic it could be to appoint one of them. Ipswich Town head coach Kieran McKenna has emerged as an attractive prospect to get Celtic back on a positive footing. But sources have told BBC Sport that Celtic could face a significant financial bill to snap up the 39-year-old.

McKenna signed a new four-year contract at Portman Road in the summer of 2024, which was worth a reported £5million-a-season. Additionally, it is understood he has a significant release clause that Celtic may be required to meet if they choose to formalise their interest. It remains to be seen whether McKenna is prepared to leave English football to forge a new chapter in Scotland - though sources have indicated the manager would be open to a move.

Ipswich are currently mid-table in the Championship following last season's relegation from the Premier League. McKenna was among the contenders for the Brentford manager's job in the summer following Thomas Frank's departure but the position was filled internally by Keith Andrews.

Ange Postecoglou is back on the market after a short and unsuccessful spell at Nottingham Forest. The Australian, who was sacked by Tottenham at the end of the 2024-25 season, lasted just 39 days at the City Ground and became the shortest-serving permanent Premier League manager.

Postecoglou failed to win any of his eight matches in charge of Forest, with two draws and six defeats across all competitions, but he is still revered by the Celtic-fanbase and is available. He spent two seasons in charge of Celtic between 2021 and 2023 and led the club to a domestic treble in his second campaign.

Former striker Robbie Keane also fits the bill as another option with close links to Celtic and someone who fully understands the club. Keane scored 16 goals in 19 appearances for the Scottish giants during a loan spell in 2010 and was named Celtic's Player of the Year for 2009-10.

The Republic of Ireland international hung up his boots in November 2018 following a short stint as player-manager at Indian Super League club ATK. In 2023, Keane was appointed manager of Israeli side Maccabi Tel Aviv and led them to a league and cup double last year. He took over at Hungarian team Ferencvaros in January and won the league title during his first season. It is understood Keane would be open to the Celtic vacancy.

Craig Bellamy took his first steps into management in 2024 with the Wales national side and is also understood to have admirers at Celtic. The 46-year-old scored eight goals in 14 appearances for the Scottish side during a loan spell in 2005.

Bellamy has overseen 14 games with Wales - winning six, drawing four and losing four and is said to be committed to the role. Wales are third in their qualifying group for the 2026 World Cup and guaranteed at least a play-off berth, so luring him away from the national side could prove difficult.

Martin O'Neill spent five years in charge of Celtic between 2000 and 2005 - winning seven trophies, including three Premiership titles. The Northern Irishman's last role in the dugout was with Nottingham Forest. He succeeded Aitor Karanka in January 2019 with the club ninth in the Championship and was sacked at the end of the season with Forest sitting in the same spot.

Speaking on Tuesday, O'Neill said: "I can't emphasise this enough, this is short term, until a permanent manager is appointed." O'Neill's first assignment comes on Wednesday when Celtic host sixth-placed Falkirk at 19:45 GMT.