Strauss, the England and Wales Cricket Board's director of cricket, told Pietersen in May that he would not be considered for an international recall.
"I think that clarity has helped," Strauss was quoted as saying by bbc.com on Monday.
England won the Ashes series 3-2 but trail 2-0 in the One-Day International (ODI) series before Tuesday's third ODI at Old Trafford.
Pietersen, 35, was initially sacked after the 5-0 whitewash in the 2013-14 Ashes series.
But Strauss believes the team has "moved on".
"The danger at that time was that particular issue would overshadow everything that happened on the pitch over the course of the summer," the former skipper said.
"What I was trying to do was provide clarity going forward so everyone knew where they stood. I think the team has moved on and the team is in a pretty good place," Strauss said.
"Some of those young guys have established themselves and that's what we will be focusing on taking England forward," he added.
England called up wicket-keeper Jonny Bairstow after deciding to rest Jos Buttler for the remaining three games of the ODI series.