The Gunners are said to have tried to sign the 19-year-old Ivory Coast centre-back this summer but ultimately made just one defensive addition, bringing in Jurrien Timber from Ajax.
It would appear that Mikel Arteta's side's interest in Diomande has not gone away, though.
According to Portuguese outlet Record, Arsenal are weighing up a fresh approach in the winter transfer window after failing with a £30m bid this summer.
And the Gunners could have to cough up considerably more than that: Sporting, the reports adds, value Diomande at £69m.
How Arsenal EVOLVED Declan Rice to beat Man United
Diomande joined Sporting from Danish club Midtjylland in January this year, having impressed on loan with Portuguese second-tier outfit Mafra during the first half of the 2022/23 season.
He went on to help his new team reach the final of the Europa League, featuring in both legs of their quarter-final victory over... Arsenal.
And Diomande's meteoric rise continues: he received his first senior Ivory Coast call-up this month, making his full international debut in an 2024 Africa Cup of Nations qualifying win against Lesotho on Saturday.
Arsenal's continued links with the teenager come after they lost Timber to an ACL injury just two games into his Gunners career, leaving them short at centre-half.
The Dutch international, a £38m arrival in July, is expected to miss the rest of the season.
More transfer stories
Meanwhile, over at Old Trafford, Manchester United might have just been handed a huge opportunity to offload Jadon Sancho after his public falling out with Erik ten Hag.
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Tom Hancock started freelancing for FourFourTwo in April 2019 and has also written for The Analyst and When Saturday Comes, among others. He supports Wycombe Wanderers and has a soft spot for Wealdstone. A self-confessed statto, he has been known to watch football with a spreadsheet (or several) open...