The Blades have been linked with Hogan for much of the summer, with further talks set to continue this week between the two clubs, who face each other at Bramall Lane on Saturday.
A loan switch leading to a permanent move is being mooted for Hogan, who has endured an injury-hit time at Villa Park after joining from Brentford for £12m in January, 2017.
Middlesbrough are poised to make a renewed move for Millwall midfielder George Saville.
A joint approach for the £5m rated Northern Ireland schemer and Lions team-mate Jed Wallace was knocked back earlier in the summer.
But Boro have maintained their interest and are aiming to strike a deal before Friday’s 5pm loan deadline.
There is speculation that Saville could join on an initial season long-loan, with an option to buy for a £5m fee.
The Teessiders are being linked with several other players, including Wigan’s Nick Powell, Cordoba striker Sergi Guardiola and Huddersfield winger Rajiv van La Parra.
Hull City are battling with Glasgow Rangers and Greek outfit AEK Athens to sign Newcastle winger Rolando Aarons, 22, a former target.
Aarons spent last season on loan in Italy’s Serie A with Hellas Verona.