The former Wimbledon striker has held discussions over a role working alongside new director of football Joe Kinnear.
The 54-year-old played under Kinnear during their time together at the Dons and remains a close ally of the Irishman.
Sunderland-born Harford had a brief spell with the Magpies as a player from August 1981 to March 1982 having launched his career at Lincoln, and went on to play for Bristol City, Birmingham, Luton, Derby, Chelsea, the Black Cats, Coventry and Wimbledon, forging a reputation as a no-nonsense frontman.
He began his coaching career at Wimbledon before following Kinnear to Luton and then Nottingham Forest, and later became a manager in his own right at Rotherham, Luton and QPR.
By the way ... Luton and Forest were relegated!
Harford's 13 months as assistant to Karl Robinson at MK Dons came to an end in June, and it was later announced he was to take up a coaching role at Millwall.
Should he be appointed to assist Kinnear, the move would do little to ease the tension at St James' which was created when Kinnear was parachuted in above manager Alan Pardew by owner Mike Ashley.
The 66-year-old Irishman's arrival was greeted with both anger and astonishment as he was put in charge of all football-related matters, but particularly the club's transfer affairs.
To date, not a single senior player has been added to the squad, while Steve Harper, Danny Simpson and James Perch have been allowed to leave, although Harper and Simpson were always moving on anyway.
With Papiss Cisse's refusal to wear the logo of sponsor Wonga on his shirt suggests he is next to leave.
RIO AVE 3 NEWCASTLE UTD 1
RIO AVE: Ederson, Tarantini, Hassan, Diego, Braga, Vilas Boas, Dias, Marcelo, Lionn, Del Valle, Wakaso.
NEWCASTLE UNITED: Alnwick (Elliot, 46); Santon (Williamson, 70), S Taylor, Yanga-Mbiwa, Dummett; Cabaye (Tiote, 46), Anita (Campbell, 76); Marveaux (Obertan, 46), Vuckic (Sissoko, 46), Gutierrez (Sammy Ameobi, 46); Gouffran (Shola Ameobi, 62).
Alan Pardew's men travelled to Portugal without star striker Papiss Cisse, who was left behind amid a disagreement with the club over his refusal to wear kit sponsored by loan company Wonga.
And Newcastle's lack of firepower proved telling as Rio Ave seized the initiative to seal a comfortable win.
Pardew plumped for a mix of youth and experience in his starting XI, with inexperienced goalkeeper Jak Alnwick and full-back Paul Dummett named alongside the likes of Yohan Cabaye, Steven Taylor and Jonas Gutierrez.
This game probably gave Pardew more questions than answers, and it will be a 45 minutes that Jak Alnwick will not forget.
Managers always play down the importance of such games, saying the result doesn't matter, the performance does ... but if Pardew is looking for positions he needs to strengthen ... he could include goalkeeper.
Tim Krul is still fighting to recover from the injury he picked up against the Mackems months ago, and Rob Elliott is not a player I'd put in the same class as others who have worn the goalkeeper's shirt - he ain't no Pavel or Shay.
Do we need cover there? You tell me!
United started slowly, and quickly found themselves two goals behind, with Egyptian striker Ahmed Hassan netting a quick-fire double in the first nine minutes.
Newcastle's worries only increased, and after 26 minutes they were 3-0 behind as midfielder Braga scrambled home from close range.
The visitors did improve somewhat as the half wore on, and will have felt unlucky not to have cut the deficit as a Cabaye effort rattled the crossbar four minutes before the break shortly after Ederson had produced a fine diving save to deny Sylvain Marveaux.
Pardew made five changes during the interval, with Rob Elliott, Sammy Ameobi, Moussa Sissoko, Gabriel Obertan and Cheick Tiote all introduced into the action.
The alterations had an impact, with Yoan Gouffran shooting wide after good work down the right from Obertan after 57 minutes.
It was Gouffran's eventual replacement that would haul Newcastle back into the game however, as Shola Ameobi steered in Obertan's right-wing cross to reduce the arrears with 14 minutes to play.
The game ended sourly for the striker, though, as he was taken to hospital afterwards for x-rays on an arm injury, which forced him off.
Newcastle could not complete the comeback, though, and it was the hosts who wasted a chance to have the final say, substitute Sandro Lima seeing his penalty saved by Rob Elliot four minutes from the end after he had been bundled over by Mike Williamson.
WE TELL IT AS IT IS - NO BULLSHIT!
PLEASE join Newcastle Utd-Mad on Facebook:-
Facebook
http://www.facebook.com/pages/Newcastleutd-mad/199695536844554
PRE-SEASON FRIENDLIES:
Pacos Ferreira (A) July 23
Blackpool (A) July 29
St Mirren (A) July 31
Rangers (A) August 6
Braga (H) August 10
RIO AVE 3 NEWCASTLE 1 (Shola Ameobi)
Alnwick (Elliot, 46); Santon (Williamson, 70), S Taylor, Yanga-Mbiwa, Dummett; Cabaye (Tiote, 46), Anita (Campbell, 76); Marveaux (Obertan, 46), Vuckic (Sissoko, 46), Gutierrez (Sammy Ameobi, 46); Gouffran (Shola Ameobi, 62).
MOTHERWELL 2 NEWCASTLE 4 (Vuckic, Gouffran, Sissoko, Marveaux)
Elliot; Tavernier, Williamson (S Taylor, 46), Yanga-Mbiwa (Streete, 82), Dummett; Sissoko (Abeid, 68), Anita (Amalfitano, 82); Obertan (Ferguson, 74), Vuckic (Marveaux, 46), Sammy Ameobi (Richardson, 82), Gouffran (Campbell, 58).
Sub not used: Alnwick.