Sheffield United announced Wednesday that they reached an agreement with Championship-bound Bournemouth, obtaining the 22-year-old's services for an undisclosed fee. Ramsdale penned a four-year deal with the club.
Ramsdale's addition follows Dean Henderson's admission that he will not extend his two-year loan at Sheffield United and will instead presumably return to parent club Manchester United to compete with David De Gea for first-choice duties.
"This is not about Dean (Henderson), it's about bringing Aaron in, but Dean was outstanding for us for two years," Wilder said.
Henderson was widely regarded as one of the Premier League's best 'keepers last season and was an influential part of Sheffield United's promotion to the top flight last summer, making 86 appearances over two seasons while at Bramall Lane.
Ramsdale had a reputable campaign in his own right, playing in all but one of the Cherries' 38 top-flight outings this past season.
Ramsdale progressed through the Blades' youth ranks before Wilder handed him a senior debut in November 2016 in the FA Cup against Leyton Orient while Sheffield United was in the third tier of English football.