"If someone like Hetmyer's not playing, you're obviously going to miss his talent," Estwick said. "He's having an outstanding season for Rajasthan Royals. He's doing very, very well. He's playing well.
"He will be missed, but at the end of the day, he's not there. He's asked not to be selected for this tour so we have to get on without him and we hope that he will make himself available for future tours."
Estwick also confirmed that West Indies' IPL players would fly straight to the Netherlands once their respective franchises' seasons have ended.
Nicholas Pooran and Romario Shepherd [both Sunrisers Hyderabad] will travel after the group stage, Kyle Mayers [Lucknow Super Giants] and Alzarri Joseph [Gujarat Titans] will both be involved in the playoffs, while Rovman Powell's itinerary will depend on whether Delhi Capitals beat Mumbai Indians in their final group game on Saturday.
"Our expectation is to win all three ODIs [in the Netherlands] but it's not going to be easy," Estwick said. "Remember, a lot of the players won't have played in conditions like the ones we'll encounter in the Netherlands.
"It's about how quickly we adjust to conditions. We've only got a couple of days' practice before we go into the first ODI so it's all about adjusting and getting used to the conditions and then executing plans as well as possible."
West Indies' series in the Netherlands comprises three ODIs in Amstelveen on May 31, June 2 and 4, while the tour of Pakistan involves three ODIs in Rawalpindi on June 8, 10 and 12.