The visitors, meanwhile, are seeking to secure their third league victory in five matches and climb into the European places in the top-flight standings.
Match preview
After finishing second in Ligue 2 and securing promotion to the top flight last season, Ajaccio are one of three Ligue 1 sides who are yet to win any of their first five matches of the new season.
The Bears lost seven of their 38 second-tier games last term, but they have already suffered four defeats in five outings this season - conceding at least twice on each occasion - as well as playing out a goalless draw with Lens.
For the third time this campaign, Ajaccio were involved in a league fixture which saw both teams reduced to 10 men, when they suffered a 2-0 defeat away at Montpellier on Wednesday. Romain Hamouma and Jonas Omlin were both dismissed in the first half either side of the opening goal from Arnaud Nordin, before Elye Wahi wrapped up all three points for the hosts in the 77th minute.
Olivier Pantaloni's side, who currently sit rock bottom of the table with just a single point, last faced Lorient during the 2019-20 Ligue 2 campaign, with the Bears claiming four points and keeping two clean sheets from their two fixtures against them.
Another strong defensive display will be required on Sunday if they are to get off the mark and climb the table, before facing an out-of-sorts Nice outfit next week.
Lorient saw their unbeaten start to the new campaign come to an end when they lost 5-2 away at Lens on Wednesday.
A brace from Terem Moffi restored parity for the visitors after Florian Sotoca and Wesley Said had put Lens two goals in front, but the hosts eventually ran away with the victory as three strikes in the final half-hour secured all three points in an action-packed encounter.
Despite defeat, Regis Le Bris will be pleased with his side's start to the season as they currently sit in seventh place with seven points, just three points and three places behind the top four.
Since returning to the top flight three seasons ago, Lorient have won only one of their seven games against a newly-promoted club.
Defensive frailties on the road in Ligue 1 have also been a concern for Les Merlus, as they have conceded 48 goals in away matches since the start of last season, more than any other top-flight club during this period.
Lorient have a decent head-to-head record against Ajaccio as they have lost only three of their last 13 meetings against them, winning six and drawing the other four.
Ajaccio Ligue 1 form:
Lorient Ligue 1 form:
Team News
Ajaccio will be without the suspended Hamouma, with 35-year-old summer signing Yoann Touzghar potentially starting in attack with Kouame Botue as a result.
Left-back Ismael Diallo is set to remain sidelined with a thigh injury, so Mohamed Youssouf could retain his place in the back four along with Clement Vidal, Oumar Gonzalez and Mickael Alphonse.
Cyrille Bayala - who found the net in Ajaccio's last home game against Lille - is expected to continue on the right wing, with Kevin Spadanuda to operate on the opposite flank.
As for Lorient, Quentin Boisgard and Igor Silva are both ruled out as they continue to recover from respective muscle and thigh injuries.
Terem Moffi, who has scored four of Lorient's seven league goals so far this term, is expected to lead the line with support set to be provided in attack by Stephane Diarra and Dango Ouattara.
Adil Aouchiche, Sirine Doucoure and Vito Mannone all arrived at the club on deadline day and will be in contention to make their debuts this weekend.
Ajaccio possible starting lineup:
Leroy; Alphonse, Gonzalez, Vidal, Youssouf; Bayala, Marchetti, Laci, Spadanuna; Touzghar, Botue
Lorient possible starting lineup:
Mvogo; Kalulu, Talbi, Laporte, Le Goff; Le Bris, Abergel, Le Fee; Diarra, Moffi, Ouattara
We say: Ajaccio 1-2 Lorient
Considering Ajaccio have conceded in every game so far this term, while Lorient have only kept one clean sheet in five outings, we can see both sides having joy in the final third on Sunday.