Northampton have sacked Aidy Boothroyd after their 4-1 defeat to Wycombe left them bottom of Sky Bet League 2.
Gareth Bale has indicated that he felt a need to be the main man at Tottenham, saying he tried to "make everything tick".
The 19-year-old England Under-21 international will stay at Hillsborough until March 9.
Wickham, who cost the Black Cats £8.1million when he joined them from Ipswich during the summer of 2011, is yet to establish himself in the first team at the Stadium of Light, but has shown signs that he is getting to grips with the Barclays Premier League in recent months.
Manager Martin O'Neill, who completed a £5million swoop for Swansea's Danny Graham on transfer deadline day, has allowed him to go out on loan because the club has only three games between now and his scheduled return date.
He said: "Now that he has good confidence, maybe getting four or five matches in that month-period in the Championship would be good news all round if he stayed clear of injury.
"My slight concern is that something happens to us - but it is three games as opposed to a host of matches in the 28-day period."