The 20-year-old earned his fourth international cap for AFCON hosts Ivory Coast in last weekend's 2-0 victory over Guinea-Bissau in their opening Group A fixture.
Diomande has quickly established himself as one of the most sought-after central defenders in Europe since bursting onto the scene with Sporting.
Since joining from Danish club FC Midtjylland in January last year, Diomande has made 38 first-team appearances for Sporting in all competitions, including 20 starts so far this season.
Diomande is understood to have has attracted interest from La Liga giants Real Madrid, with one report claiming that they are "evaluating the possibility" of luring the 6ft 3in centre-back to the Santiago Bernabeu in the summer.
Premier League trio Arsenal, Chelsea and Newcastle United have also been credited with an interest, though, and they are ready to step up their pursuit of the youngster.
Newcastle are allegedly preparing to increase their scouting efforts of Diomande over the next month as they ponder bolstering their defensive ranks before the 2024-25 campaign.
Both Arsenal and Chelsea are expected to do the same, as Portuguese news outlet Record claims that the London due are "very attentive" to Diomande and will closely monitor his performances at AFCON.
Diomande is under contract at Sporting until the summer of 2027 and is believed to be possess a release clause worth €80m (£69m).
The defender is expected to start for Ivory Coast in their next AFCON group-stage fixture against Nigeria on Thursday before the Elephants take on Equatorial Guinea four days later.
Chelsea's interest in Diomande comes at a time when they are believed to be eyeing up a long-term replacement for 39-year-old Thiago Silva.
The Brazilian veteran has entered the final six months of his contract at Stamford Bridge and the Blues hierarchy are understood to have no plans to offer him an extension.
Trevoh Chalobah and Malang Sarr are also facing uncertain futures at Chelsea as they have struggled to gain regular first-team football under Mauricio Pochettino.
Wesley Fofana, who is currently sidelined with a long-term knee injury, Axel Disasi, Benoit Badiashile and Levi Colwill are other centre-back options at Chelsea, although the latter has predominantly featured at left-back.
Arsenal, meanwhile, have had to rely heavily on William Saliba and Gabriel Magalhaes at centre-back this term due to the absence of injured summer signing Jurrien Timber.
Ben White can also play as a central defender, but has mostly operated as a right-back under Mikel Arteta, while Jakub Kiwior has been a peripheral first-team figure since joining from Spezia 12 months ago.