The first Test ended in a draw after West Indies managed to blunt the England attack in the Sir Vivian Richards Stadium.
England were left short of bowlers after Mark Wood's elbow injury ruled him out of the final day, plus Ollie Robinson remains sidelined after missing out on the first Test.
Mahmood's inclusion marked the only change to England's XI ahead of the second Test, with the Lancashire seamer deemed the best replacement for Wood.
Mahmood has played seven one-day internationals and 12 Twenty20s over the past two-and-a-half years, but this is his first chance to show his international credentials with a red-ball in hand.
England captain Joe Root was reportedly impressed by Mahmood during his spells around the Test side, and both Root and head coach Paul Collingwood together decided that he should be handed the opportunity to deliver at the Kensington Oval.
Speaking of Mahmood, Root said: "He's very mature for a guy who hasn't played a huge amount of international cricket, he has an understanding of how he wants to operate.
"He's been very impressive, he's got a slightly different trajectory and will give us a point of difference. He has done that when he's played in other formats. Clearly he has good control, especially if the ball moves with reverse swing. It's a great option to have up our sleeve."
While Mahmood has not consistently been able to clear the 90mph barrier like Wood, he represented the fastest option available and is also considered one of the best exponents of reverse swing.
With the second Test scheduled to start on March 16, Mahmood only has a matter of hours to wait until he makes his debut, with England in action at the Kensington Oval Barbados.
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