Guptill, who made a 20-ball 17 in the game against Pakistan on Tuesday, got the bruised toe after being hit by a Haris Rauf delivery in the final over of Powerplay.
To a question on whether he would play in the Pakistan Super League if he gets an opportunity, Williamson started by saying that t was a "real shame" to not have played the series in the first place.
The 60-year-old, who represented New Zealand in two Tests and three ODIs in 1990, spoke about how despite extensive precautions, a serious threat came around.
New Zealand Cricket (NZC) called off the series in Pakistan abruptly on Friday just before the first One-Day International at the Rawalpindi stadium, citing they had received a serious security threat.
The New Zealand players and officials had to undergo rapid COVID-19 tests at the airport and after all the reports came negative, they were allowed to board the flight amid tight security protocols.
Ramiz Raja said he was as disappointed as every Pakistani on the cancellation of New Zealand's tour.
Veteran pacer Shoaib Akhtar took to Twitter and wrote: "NZ just killed Pakistan cricket."
NZC chief executive David White said the players' safety is paramount for the board and it chose a responsible option.
New Zealand vs Pakistan: Kane Williamson scored 238 off 364, an innings that featured 28 fours.
Kane Williamson has started 2021 with a century. his 24th in Test cricket.