The experienced left-arm spinner will miss the rest of the 50-over competition after he was called into the Welsh Fire squad for the The Hundred.
White will have been one of the first names on Sadler's team-sheet in the opening four games of the competition, but the coach will have to look at other options for the final four group games.
And he is delighted with what he has at his disposal.
"Graeme is an important player for the club, and a solid character," said Sadler, who is in charge of the team for the One Day Cup in David Ripley's absence.
"I am really pleased for him and he deserves it, as he has been brilliant for a number of years.
"So he deserves his chance to play in The Hundred, and I know he is committed to going and enjoying the experience.
"We will obviously miss him, but we have a very strong spin department.
"We have got Simon Kerrigan who is world class and is chomping at the bit to play some white ball cricket, and Freddie (Heldreich) gives is that other dimension with a bit of mystery spin.
"We have other bowling options too.
"We have Saif Zaib and we have Rob Keogh who can bowl spin, and we have Emilio Gay who has not really been unleashed on this format, but will be when the time is right.
"That is exciting and gives us the flexibility to play the extra, extra spinner or extra seamer, depending on the conditions on the day.
"We have spoken about it as a group, and the players know that every game is independent and we will pick the best team to win whatever game on that day.
"It is about a squad, so even though players miss out and they are disappointed, they are very much in contention for the next match."
The Steelbacks, who won their first match of the competiton when they beat Derbyshire last Sunday following a defeat and two washouts, are back in action on Friday when they travel to Edgbaston to take on Birmingham Bears.