Dundee boss Paul Hartley has revealed Peter MacDonald has lost his race against time to be fit for the Tayside derby with St Johnstone at McDiarmid Park.
The prolific striker was injured against Celtic two weekends ago at Dens but his manager had hoped he would shake off the knock for the meeting with Saints.
Peaso will now have to sit out the game against his former side along with fellow injury victims Kevin Thomson and Willie Dyer.
Hartley does have a possible replacement for MacDonald in the shape of his new signing, former Scotland and Motherwell frontman David Clarkson.
He is a player the Dens boss knows well having played with him at Bristol City and he has drafted him straight into the squad for the Saints game.
Hartley said: “Peaso will be out along with Dyer and Thomson. Peaso just took a knock in the clash with Craig Gordon during the Celtic game.
“He caught his knee and is feeling it, but hopefully he will start back running at the beginning of next week.
“I think it was important getting Clarkson in to give us cover. We looked at that in terms of having good options.
“He has a lot of experience of this league and has played plenty of games for Motherwell.
“David is a player I know pretty well from my time at Bristol City. His fitness is fine, although in terms of game fitness he is a little bit behind.
“He played against the Celtic under-20s the other night. He is a little bit rusty in terms of his sharpness but he is a fit lad anyway.
“He looks after himself pretty well and is at a good age. He is a good professional and we’re working on his match fitness.
“He will be in the squad for the game at St Johnstone, so it’s another option for us.
“He’s played as a left-sided player over the past couple of years, with Bristol City and Rovers.
“But I see him as a main attacker, in the role he had at Motherwell. He’s got a good goal ratio to games, with about 60 odd goals in 250 games.
“He knows the league pretty well so we do see him as a main attacker.”
Dundee travel to Perth unbeaten so far this season.
It is a record they are determined to maintain although Hartley acknowledged the threat Tommy Wright’s side will pose to that ambition.
Hartley said: “They’ve had good success over the years.
“They lost their star player in Stevie May but they work really hard as a team and have got good quality about them. We know it will be a tough game.
“I was at their last match at Motherwell. It was a good result for them away from home, scoring late on.
“Any St Johnstone game you go into, you know you are in for a tough 90 minutes. It’s always a bit of a derby. There is a little bit of added spice to the game because of that.
“By all accounts, we are taking a large travelling support through to Perth which we always do.
“That will also be great for our players. Hopefully it will motivate them and we want to go there and put on a good performance.
“Tommy has done a terrific job there. He’s a nice guy and we’ve had plenty conversations.
“They’re still on a high from winning the Scottish Cup and have always challenged in the top six over the years even though they haven’t got huge resources.
“But hopefully we can go there and impose ourselves on them. We’ve got good qualities about us. If we’re not at our best, we’ve shown we can see a game out.
“So we go into this game with a lot of confidence. If we can take that performance from the recent Celtic game into Saturday, then hopefully we can give St Johnstone a tough game.”