PITTSBURGH -- A flare-up of Christian Yelich's occasionally balky back has forced the Brewers' slugger to withdraw from Monday’s Home Run Derby, a decision it was clear he didn’t take lightly.

Major League Baseball on Sunday named Matt Chapman of the Oakland A’s as the replacement for Yelich, who was to be the event’s top seed as the MLB leader with 31 home runs. He has missed a handful of games with back tightness but was a “go” for the Derby as recently as Friday, when Yelich and his chosen pitcher, former Marlins coach Pat Shine, participated in a timed practice for the event at PNC Park that went so well that the Pittsburgh police received a call reporting an unusually steady barrage of baseballs sailing into the Allegheny River.

But by Sunday, Yelich was held out of the Brewers’ lineup for their first half finale against the Pirates, and he was forced to make what he called the “very hard” decision to bow out of the Derby.

“I definitely don’t want to disappoint anyone or go back on a commitment that I made,” Yelich said. “I was weighing both sides. I have people traveling, people looking forward to me participating in the Derby -- close friends and family. Fans as well.

“But I have people in this clubhouse and organization, a lot of people that are counting on me to be ready for the rest of the season. Unfortunately, I just wasn’t going to be able to do it. It was definitely a tough decision and I’m definitely disappointed I can’t participate. I was really looking forward to it and it was something I really wanted to be a part of. Hopefully I’m fortunate enough to have another opportunity to do it here in the future. It just didn’t work out this year.”

Yelich said his flare-up happened Saturday during the Brewers’ rain-delayed loss at PNC Park. After a sleepless night and consultation with president of operations David Stearns and manager Craig Counsell, he made what he felt was the right decision.

As for the All-Star Game itself, Yelich still hopes to participate. He was the leading vote-getter among all National League players, and manager Dave Roberts has said he planned to start Yelich in right field.

“I’d still like to try and play. I think I’ll be able to,” Yelich said. “I just didn’t think I was going to be able to do that kind of volume of swings for what the Derby demanded. If I wasn’t going to be able to perform how I was supposed to and do it justice that it definitely deserved, I just didn’t think it’d be a great idea to do it.

“Disappointed, definitely. It was something that I really, really wanted to do. I was definitely looking forward to it. I had a lot of excitement.”

The first red flag about his health emerged Sunday morning, when Counsell posted a starting lineup for the Brewers’ first half finale later than usual, and it did not include Yelich.

“Just looking at him, I felt like we were at the red line with him, so to speak, and that a day here, he needs it,” Counsell said. “It’s important that we don’t get past that red line. So that’s where we’re at.”

Chapman will take Yelich’s spot in the Home Run Derby bracket and will face Blue Jays rookie Vladimir Guerrero Jr. in the first round.

“We spent a lot of time talking about it … but in the end, he’s got a back issue right now, and it’s scary to do an event like that with a back issue,” Counsell said. That’s the bottom line. He’s got some spasms on the lower-right side. It’s similar to that issue [earlier this year], and this is just not the event you do when that’s what’s going on with your body. He’s really making a decision for us. That’s what he’s doing. And it’s not an easy decision, because he really wants to do it, and he thinks he can win it. But he also doesn’t want to risk missing games in the second half of the season.”

Counsell is hopeful that Yelich starts the All-Star Game. The Derby and the game itself, he argued, and two different animals.

“This is not something you take lightly -- he’s starting an All-Star Game,” Counsell said. “That’s not a shoo it away-type of thing. And this is not an injured list-type of injury, by any means. I’d like him to play if he’s able. If he’s able to play and he wants to play, I think that’s a great idea.”

Yelich is already eyeing next year’s Home Run Derby. The All-Star Game is being hosted by the Los Angeles Angels in Yelich’s extended hometown.

“It doesn’t mean I’ll never get to do it ever,” Yelich said. “There’s always next year, or sometime in the future.”