The on-loan Wolves attacker was told this week that Molinuex boss Dean Saunders has decided to take up a one-year option on his contract and will recall the player once the Scottish season is over.
But Fenlon admits he has not yet admitted defeat in his bid to keep the life-long Hibs fan in Edinburgh.
He said: "We have always said we would love to keep Leigh here but it is outside of our control. We are being realistic and we're actively looking elsewhere to see if we can get his type of player in.
"It would be difficult for us to make an offer for Leigh. We're not in a position to throw money at anyone. But while he is here you always have that hope he might be here a little longer and we'll continue to have that hope."
Griffiths moved to Wolves from Dundee in 2011 but has spent the last 18-months on loan in Leith after failing to secure a first-team slot with the npower Championship side.
He now has just three Clydesdale Bank Premier League games left before he potentially returns south - starting tomorrow at Kilmarnock's Rugby Park home where he will hope to find the goals that will make him the first Hibs striker in 40 years to net 30 times in a single season.
He has already fired Hibs to the William Hill Scottish Cup final against Celtic on May 26 after back-to-back hat-tricks in the last eight against Killie and then in the semi-final with Falkirk.
Now Fenlon says the Hibees' faithful should drink up his final four games in green.
"I think the fans should be savouring Leigh's performances either way," he said. "He's scored some cracking goals in the semi-final and then against St Mirren last weekend.
"It was a fantastic strike against St Mirren and he got a tap-in at the back post and I suppose that shows he can score all kinds of goals.
"How do we replace him? Well we go about trying to keep him first. If he goes, we have a job on our hands trying to get someone to come in and play instead of him.
"That's part of football and we need to make sure we go and find the next one. We've got some fantastic young players and it's important we nurture them through. But it will be a difficult task replacing him. There's no point saying anything other than that."
Griffith's latest double against St Mirren last Saturday took his tally to seven in four games against the Buddies this season and 27 in total.
While he lags way behind Alan Gordon and Jimmy O'Rourke, who notched 42 and 34 respectively for the club during the 1972/73 season, Fenlon claims he's never worked with a better goalscorer.
"He's a better player than when he started here," the boss declared. "His all-round game has improved.
"There's no doubt he's more settled now too. He can still be a pain in the arse at times but he's a good character. I've said it all along, there's no malice in him. He just loves playing football.
"I've learned too. You are always learning, especially with the things we've had to deal with.
"Is he the best I've worked with? Technically, I don't think I've seen better. In fairness, I had a couple of players in Ireland who played at a decent level. Jason Byrne and Stephen Geoghegan were capped for the Republic of Ireland. They were good, good players and scored a lot of goals. But Leigh's all-round game is just different class."
Fenlon deserves credit himself for his handling of a player who is no stranger to off-field controversies and his desire to keep him out of the papers. In fact, Friday was the first time the player has been put up for pre-match press conference duty this season.
But the Irishman insists the Scotland international's team-mates also merit a share of the praise, saying: "Leigh has to take the majority of that credit along with his team-mates. You don't score that amount of goals without your team-mates.
"We have helped him as a group, both on and off the park. We'll continue to do that. He's a special player and we need to make sure what people talk about is what he does at the weekend.
"I was disappointed at the weekend because we got some unfair criticism over how we have managed Leigh in relation to the Press. The answer to that is that his performances on the park show we have managed him properly."