Jamie Carragher and Kenny Dalglish go back a long way. Back to the days of a lesser-known Mersey derby, Bootle Boys against their Crosby counterparts. Back to a match where the boyhood Evertonian's Bootle side were awarded a contentious late spot-kick against a Crosby team including a young Paul Dalglish. As their respective fathers clashed on the touchline, Philly Carragher, who has a reputation for being vocal, informed the Liverpool manager that he should know about dodgy penalties, given the number awarded at Anfield.
While now, as then, Dalglish is at the helm of Liverpool, much else has changed in the intervening period. It is possibly the last time either the Scot, with his suspicion of outsiders and natural instinct to protect his players, or the Scouser, another fervent believer in 'the Liverpool Way', would admit to disagreeing. In public, Anfield icons form a mutual admiration society.
In private, it may be different. While the 34-year-old is adamant he will not retire, Dalglish seems to be performing a task perhaps only someone with his standing at the club could and phasing Carragher out. It was not a task Roy Hodgson could, or perhaps would, have attempted. Since suffering a calf injury in October, though, stalwart has become substitute. Carragher has only started two league games since then; one with the added protection of being the middle of three centre-backs during the non-aggression pact with Stoke and then in Saturday's defeat to Arsenal.
Harsh as it may seem to deflect credit from the deserving Robin van Persie, Carragher could be faulted for each of the Dutchman's two goals; he was a yard behind the Arsenal captain when Bacary Sagna crossed and appealed in vain for offside before Van Persie's wondrous volleyed winner.
While it can be attributed to ring-rustiness, it illustrated why Dalglish sidelined Carragher in the first instance. Early-season errors led to goals for Bolton and Stoke and, in his absence, his sidekicks, Martin Skrtel and Daniel Agger, formed an impressive alliance. The veteran's recall came courtesy of the Dane' fractured rib, rather than a managerial rethink.
And with Agger absent for a month, the next few weeks have the feeling of a final hurrah as a first choice. Carragher reacted angrily to a television reporter at the Carling Cup final who wondered if it was the start of a farewell; though perhaps neither the time nor the place, it is a legitimate query.
After his excellent displays at last year's Copa America, the Uruguayan Sebastian Coates was not signed to be fourth choice in the long term. Moreover, Carragher has started to have an impact on the side's style of play. In autumn, Liverpool's defensive line was as deep as Chelsea's was high, with the elder statesmen forever backing off. Never genuinely quick - though it is a sign of Carragher's positional skills that only Thierry Henry really exposed it - he is now slow.
Perhaps Steve Clarke, who has drilled many a defence in his time, persuaded Dalglish a new direction was required, but improvement was evident. Liverpool only conceded three goals in the eight league games after Agger and Skrtel were paired. Each is enjoying arguably the finest season of his Anfield career now while Carragher, despite a first trophy in six seasons, is probably in the midst of his most miserable since an injury-hit 2003-04.
Since then, he has been the constant, making a barely credible 326 appearances in Rafa Benitez's reign. Like his contemporary Frank Lampard, he has a marked aversion to missing games even if, unlike the midfielder, he keeps his grievances to himself.
Much as Dalglish tries to handle him sympathetically - granting Carragher cameos with appearances in cup competitions and even a start in midfield against Manchester United - it has been, as he admitted this week, frustrating. Squad rotation suits some veterans, especially at Old Trafford, but rarely central defenders accustomed to being the cornerstone of the side. The workhorse never asked for an easy ride.
Literally and metaphorically, it is a safe assumption no-one has sweated more for the Liverpool cause. His 689 games are exceeded only by Ian Callaghan, whose record of 857 Carragher won't surpass. For one who has recently turned 34, the defender has plenty of miles on the clock.
He is one who seems burned out and is now fading away. While his current contract has another 15 months, it is hard to imagine Carragher becoming Anfield's answer to Ryan Giggs and Paul Scholes; he was not blessed with their extraordinary ability, and character accounts for much of his considerable success. While only being second in command for much of his career, he is one of Liverpool's great leaders. If Steven Gerrard represents the heart of the club for the past decade, Carragher has provided the soul. In troubled years, he was a symbol of what Liverpool should stand for. There are times, too, when it seems Dalglish is trying to rewind to his preferred era, the past, but he has moved Liverpool forward at the back. Carragher's future could lie as a club ambassador, but it is looking unlikely it will contain many matches in the middle of the defence.