Rondon's contract was selected by the Pirates on Saturday, Bill Brink of the Pittsburgh Post-Gazette reports.
The 27-year-old Rondon is one of two hard-throwing right-handers the Pirates brought up to their bullpen in advance of Saturday's game against the Cubs. Rondon has spent the season at Triple-A Indianapolis, where he's notched a 1.91 ERA and a 1.12 WHIP across 33 innings. He figures to serve in a middle-relief role with the Pirates.