Guiu joined the [Black Cats](http://www.thenorthernecho.co.uk/sport/football/sunderland) on a season-long loan earlier this summer, and has made three appearances for Regis Le Bris' side in the first month of the campaign, scoring in last week's Carabao Cup defeat to Huddersfield Town.
The terms of his loan agreement did not include a recall clause that would have enabled Chelsea to automatically trigger his return to Stamford Bridge, but the Blues hierarchy entered into discussions over such a move earlier today.
Chelsea started reassessing their options when Liam Delap suffered a serious hamstring injury in yesterday's win over Fulham, with the summer signing from Ipswich Town set to be sidelined for more than two months.
Delap's injury led to Chelsea pulling the plug on Nicolas Jackson's proposed loan move to Bayern Munich, but despite the Senegal international being told he could not complete his proposed switch, Blues officials were keen to recall Guiu.
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Sunderland's ownership group have agreed to Chelsea's proposal after talks this afternoon, with the Black Cats now expected to make attacking reinforcements of their own before the transfer window closes at 7pm tomorrow.
Sunderland were already hoping to sign a new wide attacker on deadline day, but their squad restructuring is also now expected to feature the arrival of a new forward. Whether one player is deemed capable of fulfilling both roles remains to be seen.
In Guiu's absence, Eliezer Mayenda and Wilson Isidor are Sunderland's only recognised centre-forwards, a situation Le Bris is unlikely to be happy with given the obvious risks if one or both players was to be injured.
Sunderland also remain keen to recruit a new centre-half before the window closes, with Bologna's Jhon Lucumi still regarded as a viable option despite the Serie A side's repeated insistence that the Colombian is not for sale.