The 30-year-old striker's impressive showings in training led to him penning a contract earlier this week and he is now in line for a baptism of fire debut when the West Region champions travel to Saracen Park to face Ashfield on Saturday.
Parker burst onto the Scottish football scene as a promising 16-year-old when scoring on his debut against Hibs and has led a somewhat chequered career since leaving the Perth club on a free transfer in 2004.
His subsequent spell at a Colin Hendry-managed Blackpool culminated in him scoring in their League One Play-off Final defeat of Yeovil, but since that four-year stint came to an end he has played with lower league English sides before returning to Scotland with Ayr last season.
Medda boss Chris Strain said: "There's a real spark about Keigan who is a very quick type and I have high hopes of him proving a great asset for us.
"We made the point of speaking to a number of Senior contacts about the lad and the unanimous verdict from all sources was that he will score a barrowload of goals at Junior level. I'm excited about seeing what he can do alongside our other front players.
"Ashfield's ground is so tight that it's maybe not best suited for him, however he will definitely come into contention for a jersey."
Strain added: "A big performance is needed if we are to get our own back on Ashfield.
"They beat us 3-1 at Saracen towards the end of last season and then rubbed salt in our wounds by winning 1-0 in the Evening Times Cup Final so this is one particular hat-trick I'm keen to see us avoid."
Meanwhile, Stevie Rankin insists nobody is reaching for the panic button at Ashfield – yet – but he is concerned that his playing charges have failed to win any of their last three league outings.
It only perturbs him further to be facing a fired-up Meadow on the back of his side's 3-1 defeat away to Glenafton last weekend which he claims was arguably Ashfield's worst display in nine years.
He said: "Diabolical doesn't even begin to describe our performance and only goalkeeper Steven Hall and Robert Wright could come away from Loch Park with their heads up.
"In fairness the guys have held their hands up and accepted the brickbats but now they have to show their true character in what is shaping up as a really tough game.
"The likelihood of Meadow blooding Parker is sure to see a big crowd travel and I'm hoping the atmosphere will bring out the best in my players."