PITTSBURGH -- C.J. Edwards pitched one inning in relief on Tuesday, but when Cubs manager Joe Maddon asked if the right-hander could go another, he was told no. On Wednesday, the Cubs placed Edwards on the 10-day disabled list and an MRI revealed right shoulder inflammation.
The Cubs recalled right-hander Cory Mazzoni, 28, from Triple-A Iowa on Wednesday to take Edwards' spot on the roster.
Edwards, 26, was one of the Cubs' key setup men and has nine holds and a 2.88 ERA in 25 relief outings.
"It's some kind of tenderness in his shoulder," Maddon said of Edwards. "I'm hearing he'll be throwing in a couple weeks, hopefully, but there's no set timeline on it. We're just going to calm it down and whenever he gets throwing again, he gets throwing again.
"My only concern is that he gets well and sooner rather than later. It's a long season, he's pitched a lot the last couple years and this might actually help us. I know you don't necessarily want it to be this way. We'll let it heal up and take it from there."

Pedro Strop or Justin Wilson can step into Edwards' role, Maddon said.
"Obviously, it's a big miss," Maddon said. "You saw [Tuesday] night -- put [Edwards] in against the top of the batting order -- and if you throw a lefty in there, I don't care. He handles lefties well.
"There's guys who can fill the spot, but C.J. is such a high-end performer, you hate missing him."

Mazzoni, 28, went 3-2 with a 1.25 ERA in 14 relief appearances with Iowa this season, striking out 22 batters and walking five. He walked a batter in two-thirds of an inning in Wednesday's 2-1 loss to the Pirates.
Happy return
After going 3-for-3 with a walk on Wednesday, Jason Heyward is batting .357 (10-for-28) with a double, two triples and six RBIs in 10 games since being activated from the concussion DL on May 18. That's encouraging for the right fielder.
"I'm trying to keep it simple, take it one day at a time," Heyward said. "It's early, but I hate missing time. You can't control that. It's good to be back and I'm trying to take advantage of situations when I get an opportunity to get a runner home. Outside of that, it's one day at a time, keep going out there, keep making strides and keep adding to what we have going."

Maddon has noticed.
"He's hitting the ball hard," Maddon said. "Good at-bats. He's moving really well."
Heyward has been part of a rotation of Cubs outfielders and Maddon wasn't sure if part of his and others' success is because players are getting some rest.
"There's all those moving parts that are good when you can get guys off their feet," Maddon said.
Heating up
It has been much warmer in May than April, which may be contributing to the Cubs' recent success. Entering Wednesday, they lead the Majors in on-base percentage (.357) in May and their OPS (.821) ranked second behind the Indians.
"The weather has got to have something to do with it," Maddon said. "April was so weird regarding the weather itself and missing days and having doubleheaders or moving things around. It's been an awkward beginning."