Stephen Folan joined Finn Harps before the transfer deadline and could make his debut away to Shamrock Rovers tomorrow.
The former Newcastle United defender is back in the League of Ireland after a spell in Australia with South Melbourne.
Centre-back Folan, 28, had been strongly linked with a move to north-west rivals Sligo Rovers.
But Harps boss Ollie Horgan believes he has landed a coup by signing the ex-Dundalk, Galway United, Cork City, Sligo Rovers and Limerick defender.
Horgan said: "We’re very happy to have Stephen with us for the rest of the season.
“We have a massive battle on our hands and Stephen brings a lot of experience in the league.
“There's a bit of a sprint onto the finish now and we'll need all the bodies we can gather to be able to compete."
And Folan said of his Donegal move: “I’m delighted to join and I’m looking forward to the battle ahead.
“I can't wait to get going and hopefully I can make a contribution to a successful campaign."
Pending international clearance, Folan is poised to feature against the Hoops at Tallaght Stadium.
