The pair enjoyed remarkable success together through a decade with Kilkenny, and for the bones of 15 years with Ballyhale Shamrocks, and it is with their home club that Sheffin has made his first foray as bainisteoir.
Fennelly admits to a certain element of surprise at the speed of the move given Shefflin had only finished playing for the club the year before but he also believes the 11-time All Star has already made some shrewd early moves.
Shefflin has been joined on the coaching ticket by his brother Tommy, who guided Carrickshock to an All-Ireland Intermediate title, as well as Richie O’Neill, a former Kilkenny goalkeeper who was with the county U21s last year.
“He’s dealing with a lot of younger players, which is a challenge,” said Fennelly at the launch of Sky Sports’ summer schedule.
“I know Henry very well and I’m captain of the team so I can relate and talk to him, give information on what’s going on in the dressing room.
“Because, when you become a manager you are cut off from the players to a degree. You need someone in there to figure out how things are going. No doubt he’s trying to be authentic and make his own mark but it’s definitely a huge learning curve.”
Fennelly has no doubt but that Shefflin will have absorbed plenty of ideas on the art of management from the likes of Brian Cody and James McGarry, the latter having coached with Ballyhale and the county senior.
The initial signs have been promising. Fennelly was shown the line in the club’s opening championship fixture, last month, but another sterling effort from TJ Reid propelled the six-time All-Ireland champions to a 14-point victory over Erin’s Own.
We will have to wait for Shefflin’s second act.
Kilkenny’s habit of playing off one round of club championship per month through the summer period has been ended by the new inter-county schedule and it will be beyond the Leinster Championship before we know when the next rounds are to be played.
If Shamrocks continue to prosper under the new management team, then it would be inevitable the door to an inter-county role would open for a man with Shefflin’s gilded reputation.
“I’d say he’d maybe be pushed that way whether he doesn’t want to (sic), but he has five kids as well, a big family,” said Fennelly.
“It’s a huge job in itself. He works up in Dublin two or three times a week.
“He has a lot going on so the club scene suits at the moment. County-wise, he is ambitious.
He loves hurling, loves the goal and challenge of it, so I’d say he will end up doing something but he’s a busy man as it is.
Kilkenny get their All-Ireland bid off the ground this Sunday with a Leinster Championship opener against Pat Gilroy’s Dublin in Parnell Park. Fennelly is enthused by his county’s league title, though wary of its true worth.
Whatever the health or otherwise of Cody’s latest Kilkenny offering, they appear to be in much better fettle than a Dublin side under new management, still trying to find its feet and without as many of the Cuala contingent as might have been hoped.
Fennelly knows how taxing it can be to report in for county duties on the back of long club campaigns, having won three All-Ireland titles with Ballyhale, but he senses a tweak in the priorities of young players in general these days when it comes to sport and life.
“Sport is not the be all and end all, compared to where we were at. It was the be all and end all. Concerts, social life, travelling; the world has become smaller and there’s more opportunities, so people have to understand that.
“Sport is not everything and I’m slowly understanding that. If I was a manager or coach, I would find it difficult and, with the Cuala players, there are three or four who’ve decided not to go back and as a coach that’s frustrating. It makes your job a lot harder.”