The hosts are currently second in the table despite their disappointing run, while Finn Harps occupy ninth, having only picked up 10 points from their 17 matches of the season.
Derry City, who are two-time League of Ireland Premier Division champions, made an excellent start to the season, going unbeaten in their opening nine matches, recording seven wins in the process.
The Red and Whites responded to their first loss of the season at home to Shelbourne picking up seven points from their next three games, but they are without a victory in the league since putting four goals past St Patrick's Athletic at the end of April.
Indeed, Ruaidhri Higgins's side have picked up just two points from their last five games, losing each of their last three to Shamrock Rovers, Dundalk and Sligo Rovers.
Derry are still second in the division, though, seven points behind leaders Shamrock Rovers, with Dundalk in third only a point behind and also boasting a game in hand.
The Candystripes have the third-best home record in the League of Ireland Premier Division this term, picking up 15 points from nine matches, and they will be taking on a Finn Harps outfit that have only picked up five points from their eight away fixtures this term.
The visitors will enter Friday's contest off the back of a 1-0 home loss to Dundalk on Wednesday, and they have actually now lost each of their last four league games during a disappointing run.
Finn Harps have not been victorious in the league since a 1-0 success over Shelbourne at the end of April, and the worrying run of form has left them in ninth spot in the table, nine points behind eighth-placed Drogheda United and just two clear of basement side UCD.
Ollie Horgan's side, who finished eighth in the League of Ireland Premier Division last term, will be desperate to get one over on rivals Derry in the North-West derby, which means so much to the supporters.
Derry ran out 2-1 winners when the pair locked horns in the reverse fixture last month, but the points were shared in a 2-2 draw when they last met at Brandywell Stadium back in September 2021.
Dummigan picked up the issue in the 26th minute of the team's 2-1 defeat to Sligo Rovers on Monday and could now be replaced in the starting XI by Brandon Kavanagh.
Jamie McGonigle scored his 10th league goal of the campaign in the loss last time out, and the 26-year-old will again feature in the final third of the field for the out-of-form hosts.
Head coach Horgan is expected to resist the temptation to shuffle his pack, as there were positives to be taken from their performance against Dundalk last time out.
Derry City possible starting lineup:
Maher; McEleney, McJannett, Toal, Lafferty; Boyce, Kavanagh, Patching, Thomson; Akintunde, McGonigle
Finn Harps possible starting lineup:
McGinley; Slevin, Tourish, Donelon, Boyle; Rainey, Connolly, Hery; Devers, Mahdy, McWoods
We say: Derry City 2-1 Finn Harps
Both sides will enter this match in disappointing form, but Derry have the superior quality across the field, and we are backing the home team to end their recent losing run with an important victory over their rivals.
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