As expected, the Pirates announced Thursday that they have signed the 34-year-old right-hander, who did not pitch in 2010 due to right knee surgery and signed a Minor League deal with the Phillies last winter. That contract included an out clause that Grilli could trigger on June 1, but the right-hander was on the disabled list at that time.
The Pirates also optioned infielders Pedro Ciriaco and Josh Harrison to Triple-A Indianapolis and and transferred right-handed reliever Evan Meek from the 15-day to the 60-day DL.
Though manager Clint Hurdle said Wednesday he would hold any comments on the topic until after the signing was official, he noted that Grilli is someone the club had been eyeing.
"We have interest," Hurdle said. "We have made a call on a number of people. I think what we're also letting people know is that we're not going to sit back and listen to the tremendous astronomical asks that are being presented to us for some of the other personnel we've made contact on.
"We're going to be creative, and we've talked about a number of guys who are in the Minor Leagues trying to find their way back with some Major League experience. He would fall into that category."
News of the acquisition was actually released by Grilli, who, shortly after midnight, tweeted: "Black & Yellow! Black & Yellow! Black & Yellow! Cannot wait to join the new squadron." Grilli has since followed that up with a tweet that links to an article about the Pirates.
Grilli returned to the mound in June after his DL stint and continued to pitch well for Triple-A Lehigh Valley. In 28 games this season, Grilli has a 1.98 ERA and 43 strikeouts in 32 2/3 innings. He has limited opponents to a .217 batting average.
He has played parts of eight seasons in the Majors since making his debut with Florida in 2000. In 238 career appearances -- the most recent of which was with the Rangers in 2009 -- Grilli has posted a 4.74 ERA. He has notched 262 strikeouts and walked 161.
Harrison, 24, has batted .263 with five RBIs in 30 games with the Pirates. Ciriaco, 25, has gone 0-for-6 in seven games.
Meek, a 2010 All-Star who has been sidelined since early June by right shoulder tendinitis, has gone 1-1 with a 4.40 ERA in 17 appearances with Pittsburgh this season.
The Pirates announced they will make corresponding roster moves Friday, when they open a three-game series vs. the Cardinals.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.