It might not be the standard way you would look to quantify the Leeds Rhinos legend’s impact.
For example, as one of the finest players of his generation there are the countless points he has scored, teams he has led, trophies he has lifted.
Since retirement, you can talk about the millions of pounds raised for Rob Burrow and Motor Neurone Disease Association through that remarkable feat of running seven marathons in seven days.
Interest in Zoom calls, then, are not the first thing that springs to mind as a barometer.
However, there is some reasoning to this unusual train of thought.
Sinfield was answering questions on one such press conference on Thursday, hours after it had been announced he would be leaving Emerald Headingley and his role as director of rugby at the end of the season.
At the same time as the press conference started, elsewhere, rugby union giants Leicester Tigers were busily confirming the former England captain would be their new defence coach for 2021-22.
Rugby union has a ‘good un’ there.
It is hard to quantify how much rugby league as a whole will miss him but the 40-year-old’s departure is certainly going to leave a sizeable void for the sport.
The number of people on that Zoom call illustrates one thing perfectly about Sinfield: people are interested in him.
He is a rare breed in British rugby league; someone who has managed to gain national acclaim in a sport that traditionally struggles to gain such exposure.
Sinfield’s amazing efforts last year in aid of his good friend Burrow were showcased wonderfully by the BBC and captured the hearts and minds of millions.
People not only now know more about MND – the most crucial aspect of it all – but, as a by-product of that, they know more about rugby league.
He was the first – and still only – rugby league player to be nominated for the BBC Sports Personality of the Year when he finished runner-up behind Andy Murray in 2015, the year he retired as a player, having led Leeds Rhinos to an historic treble.
Sinfield was a brilliant ambassador for the sport – and he was at pains to explain on Thursday that he still will be an ambassador for the sport “he loves.”
To the outside looking in, it might seem odd that someone leaving wants to put himself forward to continue singing its praises.
However, two things: Sinfield loves rugby league – it is in his blood – and he, more than anyone, wants to see it flourish the way so many believe it can if nourished in the right way.
That will not change because he has switched codes.
Secondly, though, Sinfield will also be painfully aware that, unfortunately, there is no-one waiting in the wings ready to take the baton from him.
He told the RLWC2021 World Cup chief executive Jon Dutton and the RFL chief executive Ralph Rimmer he will continue to do anything that is required of him.
Ironically, as he moves into union, Sinfield may well have a better platform to extol league’s virtues and gain some exposure.
That said, it is sad to think there is no way his talents can be embraced more purposefully here.
He said the director of rugby role that he took on when returning to Leeds in 2018 had altered immeasurably and now offered him no satisfaction.
Sinfield wanted to get back to more performance-orientated work but it seemed his role had drifted too far away from that and been swamped with matters that held little interest for him.
Although he had discussed with the club a change in role, Leeds had been unable to come up with one that fitted for their greatest all-time captain.
Like many, Sinfield said when he retired that he was unsure where he wanted to go post-playing but – with a degree in Sports and Exercise as well as a Masters in Sports Business – he was well placed to explore both sides: coaching/performance and administration.
Having worked as the RFL’s rugby director and as head of the England Performance Unit, as well as his role at Leeds, he has had a taste of both.
At some point, Rhinos’ long-serving chief executive Gary Hetherington will have to hand over the reins and perhaps Sinfield may have thought that might have happened sooner rather than later.
It would be no surprise if he did return to Headingley again at some point in the future in some role.
However, shortly he will be heading to union and, in fairness, many before who have followed that well-trodden path have not returned.
There are far more and far better opportunities in the 15-man code when it comes to coaching positions.
You only have to take a look at some of Sinfield’s peers to realise that.
Former Wigan and Great Britain captain Andy Farrell is Ireland head coach while his former Wigan and Lions team-mate Shaun Edwards is France defence coach, both having also served the British Lions.
Ex-Warrington Wolves hooker Jon Clarke is England’s head of strength and conditioning and former St Helens and England centre Martin Gleeson is backs coach at Wasps.
Jamie Langley, the London Broncos assistant and England Under 20s assistant coach, joined Sale Sharks in a newly-created role of peak performance coach this month. His former Bradford Bulls team-mate Paul Deacon is interim head coach.
The list goes on.
Alternatively, Sinfield’s former Leeds and England team-mate – and The Yorkshire Post columnist – Gareth Ellis worked as Hull FC football manager after retiring but soon ended up back on the training field as an assistant coach.
Sinfield will now try his hand at union as a defence coach and you would expect him to thrive.
Having watched him play for Yorkshire Carnegie when he retired from league in 2015, you could see he had a grasp of the sport.
With his famous kicking skills, it would have been intriguing to see how he would have fared as a fly-half if he had made the switch earlier than at the age of 35.
Sinfield’s innate love for rugby league ensured that never happened. You sense he will be able to make his mark on a coaching basis far more quickly.
Rugby league’s loss will be rugby union’s gain but, hopefully, Sinfield can carry on leading his true love, even if it is in a long-distance relationship. Zoom does make that easier.