Even 13 times English Premier League title winning Scottish manager, Alex Ferguson, experimented with three-at-the-back.

Louis van Gaal later presented the system as new when he deployed it with the Netherlands at the 2014 World Cup. But United had been using half-back lines well before their 1908 title triumph, when Dick Duckworth, Charlie Roberts and Alex Bell lined up as right, centre and left half.

From Half-Back Lines to Defined Roles

The shift from half-backs to more modern distinctions became clear under Wilf McGuinness in 1969–70. McGuinness, Busby’s successor, guided United to an eighth-place finish. The matchday programme acknowledged the change: Pat Crerand (#4) was listed in midfield alongside Bobby Charlton (#9). Bill Foulkes and Nobby Stiles were clearly described as twin centre-backs, flanked by full-backs. The distinction between defensive midfielders and centre-halves had arrived.

Why Three at the Back Faltered

The late 1960s and early 1970s exposed the system’s fragility. Before 1965 there were no substitutes. From 1965 until 1988, only one was allowed. Injuries became devastating. Without Crerand, managers turned to David Sadler, who could play as a centre-half or centre-forward, or John Fitzpatrick at half-back with Steve James at centre-half. Utility players were crucial, but specialisation suffered. Squads were small — 16 regulars playing 30-plus games — and systems bent to availability rather than design.

United paid the price. Relegated in 1973–74, they finished 21st out of 22, with Sammy McIlroy top-scoring on six goals. The team still featured remnants of the 1968 European Cup winners, but the side had become a patchwork of defenders forced into midfield. Until 1988, when a second outfield substitute was permitted, managers picked utility men as the lone “twelfth man,” skewing balance away from attack.

A 1970–71 Snapshot

Busby returned on 29 December 1970 to replace McGuinness. United finished eighth again. Their League Cup run ended with another semi-final defeat to Aston Villa. The squad list told the story: Crerand (24 apps), Sadler (32), Stiles (17), Fitzpatrick (35), Paul Edwards (29+1), Francis Burns (16+4), Steve James (13), Ian Ure (13), Willie Watson (8), Tommy O’Neil (1), Tony Young (0+1) and Ian Donald (0). Thirteen of 21 outfielders were classed as backs. Only Alan Gowling (17+3), Brian Kidd (24+1) and Denis Law (28) were labelled as forwards.

The scramble to be the single substitute hurt United badly. Law top-scored with 15, while Gowling and Kidd both had eight. Frank O’Farrell arrived from Leicester in 1971–72. McIlroy scored on his debut against Manchester City in a 3–3 derby. George Best hit 18 in 40. Ian Storey-Moore joined from Nottingham Forest for £200,000 and scored five in 11. Still, United finished eighth again. O’Farrell was sacked in December 1972, replaced by Scotland manager Tommy Docherty. Charlton top-scored with just six as United scraped survival in 1972–73, before being relegated under Docherty in 1973–74.

Promotion and the 1966 Template

Promotion came in 1974–75, with Stuart Pearson, a £200,000 signing from Hull City, scoring 17 league goals. The tactical climate of the time still mattered. England’s 1966 World Cup win came with no substitutes and a half-back line of Bobby Moore, Jack Charlton and Nobby Stiles. Injuries or dismissals would have forced reshuffles on the pitch itself. Later, the single-substitute rule nudged managers to push half-backs into midfield while keeping reserve centre-backs in the XI.

Replacing Bill Foulkes

Bill Foulkes had been a right-back in United’s 1955–56 and 1956–57 title teams before Busby moved him to centre-half after the 1958 Munich disaster. Replacing him became a decade-long problem. Youth product Steve James debuted at Liverpool in 1968. Ian Ure joined from Arsenal in 1969. Docherty later signed Jim Holton from Shrewsbury Town in 1973. Yet none provided long-term stability. Martin Buchan, signed by O’Farrell from Aberdeen in 1972, became the defensive mainstay, initially as a full-back but later at centre-half.

Brian Greenhoff and the Half-Back Debate

Brian Greenhoff, 5ft 9in, emerged as a central defensive midfielder in the early 1970s. Alongside Buchan and Tommy Jackson, he formed part of Docherty’s half-back line. But by 1978, after the £500,000 arrival of Gordon McQueen from Leeds, Greenhoff’s role diminished. McQueen and Buchan established a tall, strong pairing at centre-half, separating defence and midfield more clearly than before.

Big Ron and the Rise of Robson

Dave Sexton was replaced by Ron Atkinson, who immediately signed Bryan Robson from West Brom for £1.5m in 1981. Robson, later England captain, increased the distinction between midfield and defence. Atkinson’s side won the FA Cups of 1983 and 1985, the latter remembered for Kevin Moran’s red card and Norman Whiteside’s extra-time winner against Everton. Yet Atkinson alienated fans by selling top scorer Mark Hughes to Barcelona in 1986. Alex Ferguson arrived from Aberdeen soon after, bringing Hughes back in 1988.

Ferguson, Substitutions, and 1999 Glory

The rule change in 1988, allowing two substitutes from five, and later three from seven in 1995, freed Ferguson tactically. He no longer had to think only in terms of injured players. He could make strategic changes. The pinnacle came in 1999, when Teddy Sheringham and Ole Gunnar Solskjaer came off the bench to score stoppage-time goals and beat Bayern Munich 2–1 in the Champions League final.

Ferguson’s 13 titles were built on a solid back four. Centre-halves included Kevin Moran, Paul McGrath, Graeme Hogg, Steve Bruce, Gary Pallister, David May, Ronny Johnsen, Jaap Stam, Wes Brown, Laurent Blanc, Rio Ferdinand, Nemanja Vidić, Jonny Evans, Chris Smalling and Phil Jones. Strikers thrived from service by wingers, while Ferguson used subs for decisive attacking interventions. His flirtation with three at the back was brief. For him, the system echoed Busby’s half-backs, but modern football demanded proactive use of the bench.

After Ferguson: Regression to the Back Three

After Ferguson retired, United drifted back towards three centre-backs. Van Gaal won the FA Cup in 2016, José Mourinho claimed the League Cup and Europa League in 2017, and Ole Gunnar Solskjaer guided the team to the 2021 Europa League final, which ended in a penalty shootout defeat. Erik ten Hag later delivered the 2023 League Cup and 2024 FA Cup. But reliance on three centre-halves remained controversial. When Ruben Amorim was appointed in 2024, scepticism grew. Defeat to Spurs in the 2025 Europa League final — with Leny Yoro, Harry Maguire and Luke Shaw forming the back three — reinforced doubts. Brennan Johnson’s 42nd-minute goal, poked home after Shaw failed to clear a cross, summed up the problem.

Conclusion: From half-back lines to back threes, United’s history shows the pitfalls of defensive overload. Injuries, small squads and the obsession with utility players damaged the club in the 1970s. Only when substitutions expanded did Ferguson build a dynasty on a back four and attacking intent. The modern return to three at the back remains, for many fans, a retrograde step.