In 11 appearances, Gregg had a 10.13 ERA with 12 runs, 13 hits, five walks, 14 strikeouts and three home runs over 10 2/3 innings. It made him a lightning rod for Reds fans, starting with when he blew a lead on Opening Day vs. the Pirates.
"It's unfortunate. I know that the fans never got to see the best of Kevin," Reds manager Bryan Price said. "We felt that in the six weeks that we had him in Spring Training that he was a guy who could pitch the eighth inning for us with his background as a setup man and a closer."
Gregg, who was making $1.5 million this season, made his final appearance for the Reds on Thursday in a 7-2 loss to the Pirates. He entered in the seventh inning with Cincinnati trailing by one run and left with the club trailing by four. In his two-thirds of an inning, he gave up three earned runs, three hits and two walks.
"His stuff looked good, he had velocity and the split-finger and the breaking ball and it just never came to -- even from, unfortunately, Opening Day with the two-run homer to tie the game," Price said. "That was very difficult. Sometimes it's tough to chase that off. He's a professional, he's a great guy, he's a tremendous worker. He was doing everything he could to get back on top, but it just didn't happen and now he'll be on his way to the next opportunity."
The Reds' bullpen entered Monday 30th out of 30 Major League clubs with a 5.56 ERA, as relievers like Burke Badenhop and Jumbo Diaz have also had a number of rough games.
One type of pitcher Price has longed to have in his bullpen was a durable long man in the style of Alfredo Simon, who had strong 2012-13 seasons before going into the rotation last season and getting traded to Detroit in the offseason. Villarreal, in his third big league callup this season after several the past two seasons, could be that type of pitcher. He worked three scoreless and hitless innings for Louisville on May 4.
"All of our people that saw him felt like it was one of the best games they've seen him in recent history as far as performance," Price said. "It's one of the things that led Pedro to being that 26th man in the doubleheader in Chicago and to be considered when we made the roster move."
Villarreal was last up on Saturday as the 26th man on Saturday in Game 2 of a doubleheader against the White Sox. It didn't go well as he gave up three earned runs and four hits over two-thirds of an inning.
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.