Chris Armstrong has joined Championship rivals Reading for an initial fee of £500,000 which could rise to £800,000.

The 26 year old who joined United in summer 2003 for £100,000 from Oldham made 84 league starts for the Blades, scoring six goals.

At home at left-back or in midfield Armstrong was brave and tenacious and overcame a potentially career-threatening knee injury at United to force his way back into the reckoning.

Although he wasn't in the starting eleven in the league this season manager Kevin Blackwell wasn't looking to offload the versatile squad man:

"I didn't have any intention of letting him go but the offer came in and, with his immediate chances of a first-team place a bit limited, I didn't feel it proper to deny him the chance of a good move for him."

Blackwell admits that he has never before been in a situation in which he could afford to let such a player leave:

"Looking at our squad I feel that for the first time in my managerial career I can actually build a team whilst I already have a good one, because of the quality of this squad.

"With previous clubs I have had to sell first before being able to bring somebody in which makes things a lot more difficult. Now I have the luxury of controlling when players leave to a large extent."

With Gary Naysmith in possession of the left-back position the question of covering the Scottish International was uppermost in Blackwell's mind:

"Sun Jihai can play at left-back, Derek Geary has done it on many occasions, Stephen Quinn could do it a push and we have Kyle Naughton coming on well.

"I watched David Carney play there for Australia only last week so I am not short of options -including loans - should Gary Naysmith need cover until a more permanent solution could be found."

With plenty of speculation surrounding potential bids for other Blades players, Blackwell refused to comment before sanctioning Armstrong's departure:

"Chris was an apprentice at Bury when I was there with Neil Warnock so I know what he is about - he's a great lad to have around, a good professional and he came to a great club in Sheffield United. He has been a good servant and we wish him all the best."