Ireland's James McCarthy can bring tepid Toffees to the boil at Anfield
Allardyce's men have shown little in big games but midfielder's display against United must be a marker
Seamus Coleman suffered a gut-wrenching broken leg. James McCarthy endured the Chinese torture of a hundred tweaks and twinges of the hamstring which made him nothing so much as a bitter source of dissension between his former Everton manager Ronald Koeman and Ireland's Martin O'Neill.
Both players deserved a whole lot better, for both their ability and their love of battle.
This week, though, and within the powers of any manager to heal potentially career-wrecking setbacks, those losses of momentum which can sometimes prove unshakeable, Big Sam Allardyce went out of his way to attend to their wounds.
The new manager of Everton, who was given the brief of stopping a slide into the relegation zone, pointed out that Coleman remained a huge force in the team's ability to see themselves as natural-born winners.
Allardyce's tribute to McCarthy, given that he was appearing in the team for only the second time this season and for just 28 minutes of a generally dispiriting home defeat by Manchester United, ran even deeper.
He said that a very dark hour, a time when he was beginning to despair of his team's ability to make any kind of fight against United, McCarthy was no less than a ray of 'shining light'.
He was a player filled with pride, with the kind of competitive zeal that tends to be bestowed in the cradle. What's more, he found the edge to make a tackle, a winning one, and then went on to make another. Where might such endeavour end?
Admirers of a player of prodigious commitment can only hope that it will be in his re-establishment in the blue shirt of Everton and the green of Ireland.
Whether or not he starts in tonight's FA Cup tie at Anfield will be a matter of careful physical analysis of the effects of a stint that was, in all the circumstances, filled with a remarkable intensity.
But with Everton so flat against Liverpool at Anfield in the league and the same for so long against United, Allardyce must be tempted to throw McCarthy into the mix to bring the temperature close to boiling point rather than the tepidness they have managed in those encounters.
Wayne Rooney, still luxuriating in the status of full-blown prodigal son local hero, trailed off the field after a feeble climax to his much anticipated performance against his old club and the Goodison crowd were clearly less than enamoured by Allardyce's decision to replace him with McCarthy.
For McCarthy, the booing might have been sounding on another planet.
He had his own challenge, his own universe to engage, and if Big Sam is not always notable for his delicacy he hit some fine and sensitive notes after McCarthy stretched himself to the limits of his will and his current physical capacity. Said Allardyce: "There is still some doubt in James's mind because of the length of time he has been out and the injury recurring in the same area. We are managing the situation delicately.
"It is not an ideal situation to be in and James has been out 18 months to two years. We will try to overcome the problem.
"If we can also get Seamus back, and Leighton Baines in also, we can be very confident we will get better."
Big Sam's emphasis on the importance of competitive character after defeat by a recently erratic United spoke, certainly, of a manager who had stepped beyond the kind of sound-bite arias which have been recently pouring from conquering New Year's Day rival Jose Mourinho.
"I was particularly impressed by the way James McCarthy went about things. He actually went and tackled somebody and showed the rest of our team how we had to go about the job of shutting down United."
The praise, from a manager whose post-defeat mood can sometimes be relentlessly dark, was a striking endorsement of the judgment of former Everton manager and current Belgian boss Roberto Martinez, who took McCarthy to both Wigan Athletic and Everton, the latter move then coming at an eyebrow-raising £13million.
At the time Martinez could not have been more confident of the value of the deal, saying: "The investment we made in James was a big one but it was a safe investment because I know his character inside out. Everyone can find out about character by watching the games but when you get to work with a player, get to know his character, you can be sure that you have made a good investment.
"This is very important for what I want to achieve at Everton. The character side of things is huge. I want a team who respect each other, know each other and have that urgency to get the ball back - but with composure."
Quite some time has passed, some ambitions have changed for Martinez, but there is always a special satisfaction that comes with a judgement that is confirmed down the years, which may at times be endangered by such passing circumstances as nagging injury, but is still hard and durable.
That was the status of Roberto Martinez's first assessment of McCarthy as Manchester United threatened to run Everton off their own park.
Allardyce approved it at a time when his thoughts might naturally have been running along a more negative course. He made the assessment of an embattled pro, someone who needed to remind himself of what strengths he still had at his disposal.
He says that he is managing the fitness challenge of James McCarthy with some 'delicacy.' It may not be the kind of word that naturally pops off the tongue of Big Sam Allardyce. But then no one ever accused him of lacking a hard professional instinct and this week he was plainly convinced that James McCarthy, at 27, is worth the trouble.