"The thumb has been put in a splint and is expected to take four to six weeks to recover."
There are worse times to get injured, as while Ferguson will miss three Twenty20 clashes, the Black Caps don't play another international match for two months, with Stead hoping to have the Auckland right-armer available for their next slate of games.
"We're optimistic he'll be available for the five-game T20 series against England."
That series starts on November 1, with Ferguson likely needing to get top-level bowling under his belt ahead of a possible appearance in the Black Caps' two-match test series against England, which begins on November 21.
The speedster is expected to make his test debut this summer, with the English series a strong option to introduce Ferguson to test cricket, ahead of a much-anticipated three-test series in Australia in December and January.
The Black Caps have opted not to name a replacement for Ferguson, with seamers Tim Southee, Scott Kuggeleijn and Seth Rance all playing in the opening Twenty20 in Pallekele this morning, and a 13-man squad to be picked from for the following clashes on Wednesday and Saturday morning.