In theory, in Gaelic games there shouldn't be a more difficult relationship than that between a goalkeeper and his understudy.
Without the fluidity that exists in defence, attack and even midfield, being a reserve 'keeper must surely stir difficult emotions. How do you strike the balance between wanting what's right for your team and wanting what's right for yourself?
Get stuck in the slipstream of the right 'keeper in a successful team and there is every chance that your career will pass you by.
In the course of a record-breaking 17-year career, Tipperary's Brendan Cummins has seen 10 'second in commands' come and go -- Eoin Kelly even filled the role for one match, the 2000 All-Ireland quarter-final against Galway.
Only once has Cummins been displaced, when Gerry Kennedy took over for a number of games in the qualifiers and the All-Ireland quarter-final in 2007 at the behest of then manager 'Babs' Keating.
But for the most part, a lot of prospective inter-county goalkeeping careers were over before they ever really started in Tipperary. The same goalkeeping black hole surfaced in Wexford with Damien Fitzhenry, and in Clare with Davy Fitzgerald.
Reserve 'keepers in such company generally don't wait around too long enough to allow the frustration to set in -- they see the writing on the wall.
All this makes the relationship between the trio of Cork 'keepers over the last seven seasons all the more remarkable.
Martin Coleman and Anthony Nash are not household names, but between them they have given 17 years of service to Cork hurling -- and have just a single championship appearance each to show for it.
Life as No 2 and No 3 to Donal Og Cusack has surely tested their patience, but it is testament to the 'community' of 'keepers that Donal O'Grady introduced in 2003 when he took over as manager that Coleman and Nash have stayed on.
The close bond that has developed was reflected on by Cusack in his memoirs three years ago.
"We are in competition but we are friends," he said of the relationship between Nash, Coleman and himself.
"People would have the impression that between us three 'keepers there would be resentment and and jockeying and one-upmanship. Not so.
"I'll hope that whenever I am gone they will know that I tried to create as good an environment for them as for myself and never ever did I try to steal a march on them for anything."
Coleman's tenure stretches back to O'Grady's arrival when he shared understudy duties with Paul Morrissey for three years. When Morrissey departed at the end of '05, Nash was introduced and the Kanturk man has served in the wings for seven seasons now. As apprenticeships go, they don't get much longer.
Nash was 'keeper in '07 when Cusack was suspended after 'Semplegate' for the Munster semi-final as Cork leaked five goals, while Coleman came in to the Galway qualifier the following year when Cusack was sent off.
For the most recent league final against Kilkenny, Coleman deputised after Cusack's ruptured Achilles heel ruled him out for the season.
It was a difficult afternoon for Coleman. In the opening half Kilkenny hit Cork for three goals, two of which the 'keeper was accountable for. Now it's Nash's time to feel the chill of so much Championship inactivity.