Callum O'Hare is on the brink of joining Wrexham for around £7m, leaving Sheffield United with precious little time to replace a key attacking player and questions over how much of the fee will be reinvested.

Callum O'Hare has arrived in Wrexham for his medical with the ambitious Welsh side as Sheffield United's recruitment staff are handed the unenviable task of replacing him in the final throes of the transfer window. The summer madness ends tonight at 11pm.

And despite manager Chris Wilder's hopes that United's outgoing business was done, the Blades hierarchy accepted an offer for O'Hare from Wrexham last night. The total package, we are told, is around £7m which, from a business perspective, is not a bad deal for a player signed for free and approaching the twilight of his career.

The acid test now will be how he is replaced. What is the succession plan from the top down? The emphasis of late has been on frees and loans and sources close to the club indicated that remains the primary route for a O'Hare replacement, although a portion of the fee may be allocated if the right sort of permanent deal becomes available.

What is certain is that United have to act quickly. They also have the added distraction of a game this evening, with O'Hare's expected absence also impacting on United's hopes of picking up a first three points of the season at home to Bolton Wanderers.

If, or more likely when, he does depart, then United have sold three players who together were involved in 60 per cent of their goals scored last season. Gus Hamer's departure seemed inevitable but Andre Brooks' move to Norwich City was a big blow. For many, O'Hare's sale appears to be the final straw.

Reyes Cleary of Barnsley has been touted as a potential replacement but boss Wilder is understood to want a player capable of playing as a No.10, as O'Hare did so well for him since arriving from Coventry City. Barnsley turned down offers from elsewhere in the Championship earlier this summer which were understood to be around £3m, and wanted more.

The problem for United is that the market they have been operating in does not exactly lend itself to replacing a player of O'Hare's profile at short notice.

The club have spent much of the summer being restricted to free transfers and loans, only for their approach to shift and then shift again as the window has progressed. Now, with the deadline looming, they have lost one of their key attacking players and there’s still uncertainty over whether some, all or none of the £7m package will be reinvested.

That decision will tell us plenty about what is happening behind the scenes at Bramall Lane. The financial limitations United are operating under are no secret, with Wilder admitting yesterday: "We're not in a position just to go and buy. We understand the market we're in.”

That was before O'Hare's impending departure became a reality. Now the question is whether United's situation has changed with it. United’s transfer strategy has flipped and flopped throughout the summer - and the owners now have only a few hours to show there is actually a plan behind it.