Scouts from the Elland Road outfit watched the striker during Saturday’s pre-season friendly against Accrington Stanley.
The 23-year-old could leave Ewood Park this summer and there is plenty of interest from the Premier League in securing him.
Forest have been monitoring him again, with West Ham also thought to be keen on signing him during the transfer window.
Last season was Brereton Diaz’s coming of age.
He was remarkable in front of goal and showcased some lethal finishing during a 22-goal haul that saw Tony Mowbray’s team flirt with a play-off place.
Interest in Brereton Diaz isn’t only coming from domestic clubs either.
La Liga clubs have also been watching him, with Sevilla thought to hold a keen interest in the young talisman.
Brereton Diaz is now a full international with Chile and has four goals from 14 appearances to his name.
Leeds scout Brereton Diaz and Forest won’t be re-signing him
This link from TEAMtalk seemed like an idle piece of speculation in the first place.
Forest have now signed Taiwo Awoniyi and if another striker is added it’s likely to be a poacher to replace Lewis Grabban.
Brereton Diaz has been something of a late bloomer.
He was subject to criticism and ridicule prior to the 2021/22 campaign and Premier League football would be a step up.
The youngster is still at a nice age to continue developing but he’s ultimately enjoyed just one fruitful season in front of goal.
If he can score goals on a consistent basis then he could be worth an absolute fortune.
As a result, he might be better off showing some loyalty to Blackburn and staying put in the Championship for another season.
Leeds might be willing to test the water with a bid for Brereton Diaz as they go in search of a striker.
Forest won’t be there and the City Ground recruitment team will be exploring other avenues of interest this summer.