An injury has forced UFC welterweight Thiago Alves off of the Aug. 17 UFC on Fox Sports 1 fight card in Boston.
UFC officials made the announcement on Wednesday.
Pyle (25-8-1) last competed on May 25 at UFC 160, winning a split decision over Rick Story. He is currently riding a four-fight winning streak.
Brown is on a winning streak of his own, stringing together five consecutive wins inside the Octagon. He has finished four of his last five opponents.
UFC on Fox Sports 1: Shogun vs. Sonnen takes place at the TD Garden in Boston on Aug. 17. It is headlined by a light heavyweight match-up between former titleholder Mauricio “Shogun” Rua and Chael Sonnen. Heavyweight contenders Alistair Overeem and Travis Browne face off in the co-main event.