The game, well into its third day at Chelmsford, is England's final tune-up for the Ashes series.
But with two of Essex's bowlers, David Masters and Tymal Mills, suffering injuries and depleting the attack, England asked for two replacements to be drafted in for the sake of practice.
One, Reece Topley, had been rested by Essex for the match, but the other, Boyd Rankin, represents Warwickshire and was originally part of the England squad.
The crowd were less than happy about the switch, given the fact that it rendered the match no longer an official contest.
Particularly affected was leg-spinner Tom Craddock, who in first-class conditions in the first-innings had bagged a five-wicket haul against his country. That will no longer be counted on his record, along with Tim Bresnan's century in the same innings.