Andy Moran says he's concerned that some of Mayo's most experienced players haven't seen enough game time ahead of the start of the Connacht SFC on Sunday.
James Horan named a team on Friday that shows seven championship debutants for the clash with Leitrim at Avantcard Páirc Seán Mac Diarmada.
The Green above the Red were relegated from Division 1 of the Allianz League last Sunday, despite two strong performances in their games since the resumption.
Moran, who made 182 appearances for the westerners in a 17-season inter-county career, expects Mayo to clear Sunday's hurdle, but he has his concerns ahead of potential provincial semi-final with Roscommon to come the following weekend.
"Usually after a game like we're having on Sunday, if you win that you'd have three or four weeks until your next game," he said on RTÉ's Game On.
"It's just that it's so quick now, I'm a bit fearful. When you're trying to get primed and ready for a really big game... you know yourself, no matter what sport you're in.
"Sometimes you need a game, maybe two games, to get yourself right. But if you look at the likes of Donal Vaughan, Chris Barrett, Seamus O'Se, Tom Parsons, they literally haven't played a minute since we came back from lockdown.
"With the youth, it's absolutely brilliant, such a joyful experience for them. It's great for Mayo football to be producing the likes of Tommy Conroy and Ryan O'Donoghue - really good players.
"I'd be just worried that in a week's time these guys could be undercooked going into a really big game."
Speaking on the same show, Kildare great Johnny Doyle said that for Horan, it's about making his squad as competitive as possible, with bigger tests to come.
"I'm not writing off Leitrim because this is a two-horse race," he pointed out.
"As we all know, anything can happen. I think James Horan will be probably looking to create a bit of competition within the Mayo within that squad.
"He'll be saying to the new players, 'I know we've got All-Stars on the sideline... you've got the jersey now, hold on to it. Make sure Tom Parsons, or whoever, doesn't just come and take it off you'.
"If you can create that competition it's a very strong place to be in as well."
Follow Leitrim v Mayo via our live blog or watch it live on the RTÉ News channel, Sunday, 1.15pm