He joins the Blades as a direct replacement for Rob Hulse, who joined Derby yesterday for £1.75million.

Henderson, 26, has signed a four-year contract and the fee could rise depending on his achievements at Bramall Lane.

Doncaster-born Henderson said: "This is a great move for me, coming back home. I've met the lads and there is quality in abundance here."

Meanwhile Premier League new boys Hull City eased to a 3-0 victory at Chesterfield with goals from Geovanni, Dean Windass and Caleb Folan.

Peter Halmosi, a £2million signing from Plymouth last week, started the game but it was another newcomer in the form of Brazilian Geovanni who opened the scoring from close range on the half hour.

Halmosi created the second just before half-time when he crossed for veteran striker Windass to tap in with Folan heading home the third in the 78th minute.

Elsewhere, Sheffield Wednesday ran out 4-1 winners at MK Dons as goals from Deon Burton (two), Etienne Esajas and Jermaine Johnson overturned Florian Sturm's third-minute opener.

Ends