Australia didn't play spinner Nathan Lyon - who has 562 Test wickets to his name - in the ongoing day-night Test against West Indies because that data was against him. Notably, Lyon has 43 wickets to his name in day/nights Tests - joint-second most along with Pat Cummins and only behind Mitchell Starc's 75 for not only Australia but in Test history. This is also the first time Lyon has been overlooked apart from 2013 Ashes where Ashton Agar was preferred initially. Lyon is also Australia joint-second highest wicket-taker along with Glenn McGrath and the only active bowler have more than 400 Test wickets to his name.
"It's something that wasn't front of mind, certainly a difficult [decision], but we thought the exceptional circumstances justified having the four quicks so that we could rotate those guys and keep the pressure on," Aussie selector Tony Dodemaide said as reported by ESPNCricinfo. "On a well-grassed surface and a hard surface with lots of night time play hours, that was the best way to win the game."
Dodemaide referred to the last played at the ongoing Test's venue - Barbados - which had a limited impact by spinner. Still, you don't drop a spinner like Lyon based on the data from one Test. The Aussie selector admitted that it was lack of data in support of spinners which played a part in fielding four-pronged pace attack as Australia look to clean sweep the three-Test series.
"The key in here is it's a conditions-based decision to go with the four quicks," Dodemaide said. "What we found here with the limited data that we have on particularly the pink Dukes ball… [is] that it actually behaves a little differently to the Kookaburra one. It doesn't go as soft," he added.

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