The England and Wales Cricket Board decided to end the batsman's international career following the Test team's dismal Ashes defeat in Australia in the winter.
The controversy surrounding the decision has been prevalent since the announcement was made, with television host Piers Morgan criticising Cook and Matt Prior for their involvement in Pietersen's departure.
This week, Cook described the move as a "brave call" and that it "took a lot of guts" to make the decision, but Pietersen's wife Jessica Taylor chose to mock the England skipper on Twitter.
Wow. Guts? Really? 😂😂😂😂😂😂😂😂😂😂— Jessica Taylor (@JessicaLibertyX) April 1, 2014
Cook also claimed this week that he will reveal the decisions behind Pietersen's omission "soon".