Most complaints have been around the strictness of the rules, rather than the principle itself or specific cases.
Somerset coach Jason Kerr said Tom Kohler-Cadmore was unable to hold a bat and Lewis Goldsworthy had a severe hamstring tear after their injuries last weekend, while Yorkshire seamers Jhye Richardson and Jack White had food poisoning.
Moores said seamer Fergus O’Neill was unable to bowl on the final day against Glamorgan but was already down on pace the previous day. O’Neill was replaced by Lyndon James, who took two wickets in a 192-run win.
Glamorgan’s Carlson said his complaints were “no slight on Notts whatsoever”.
“A guy who hadn’t played cricket for three days to then come in and bowl, obviously that’s an advantage,” he added.
“The thinking behind bringing in the rule is sound, but I think it has to be ironed out in terms of the way it does get done.”
The ECB has implemented more relaxed restrictions than other nations.
It wants to keep the quality of cricket high by not having players with serious injuries struggling through matches – as seen with England’s Chris Woakes in the fifth Test against India last summer.
In Australia the ‘stand-down period’ – the period a replaced player is then unavailable for – during the most recent season was 12 days, but in the UK it is only eight.
There is also no stand-down period for players whose team do not play in the next round of fixtures – as is the case with Nottinghamshire, Glamorgan and Yorkshire this week – or for the final round in a season.
The Australian laws also only allowed one substitute per match and ruled that any change had to be made before the end of day two, thus reducing the advantage of a fresh player coming into a four-day match late on.
When explaining the rules last month, ECB head of cricket operations Alan Fordham said the governing body would be relying on the co-operation of the counties in not pushing the rules to gain an advantage.
“If teams are going to start pushing at the edges of the regulation then it risks the chance we will have to backpedal,” he said.