Neshek has a 3.52 ERA in 23 innings with the Padres this season.
Manager Bud Black said the biggest reason the Padres chose Neshek and not young righty Anthony Bass was that he would like to have Bass as a long man coming out of the bullpen.
"Pat needs to work on a few things, too -- he's gotta get that ball off the plate a little more," Black said. "But it's more that Anthony gives us truer length out of the bullpen."
Neshek was sent to Triple-A Tucson earlier this year before being recalled in mid-May. With Tucson, he is 1-1 with a 1.86 ERA in nine games.