MILWAUKEE -- It was a tough night at the ballpark for Ryan Braun.
First, the Brewers slugger accidentally knocked shortstop Jean Segura out of the game after hitting him in the head with his bat while warming up on the top steps of the dugout in the first. Braun departed himself after the eighth with a slight chest muscle strain.
Manager Ron Roenicke said Segura didn't have a concussion or fractures, but needed stitches to close a gash on his face. Segura might miss a few days, while Braun labeled himself as day to day.
Foremost in Braun's mind was that Segura seemed to be OK after the scary moment.
"Obviously, it's never something that's done intentionally," Braun said. "You know whenever you're involved in a situation like that, I think it puts life in perspective and you realize how insignificant baseball is. Thank God from everything we've heard he's OK."
Estrada (2-1) threw 7 2/3 strong innings with nine strikeouts. Jeff Bianchi went 2-for-4, entering the game as a pinch hitter in the first for Segura.
The Brewers had to take a few moments to regroup after seeing Segura on the floor of the dugout in pain. He had to be helped to the clubhouse.
Braun was facing the field on the top steps of the dugout, where he normally stations himself for his warmup routine. Segura, who was batting second ahead of third-place hitter Braun, was coming up the steps behind him, and a TV replay showed the All-Star shortstop getting it on the right side of the head.
"It bugged me all game but it's one of those things you hope you can prevent. I know Braunny felt bad," Roenicke said. "Bianchi came in and did a great job for him."
Wood had his toughest outing of the season, yielding five runs and seven hits in 5 2/3 innings.
"It was a grind and a battle tonight," he said. "I didn't have my 'A' game. I was missing balls and falling behind hitters."
Estrada retired the first 10 hitters he faced -- a few on flyballs deep into the outfield -- before Luis Valbuena turned on a 2-0 fastball for a solo homer to right.
The righty then retired 10 in a row again, effectively mixing a changeup and curveball with fastball in the high 80s.
He maintained control until Welington Castillo hit a two-run shot in the eighth to get the Cubs within two. Estrada departed having allowed four hits and no walks.
"It's the best I've felt so far since spring training," Estrada said. "The last couple games, I just haven't felt like myself. But today I did."
Chicago, which lost its fourth straight, is already 10 1/2 games back in the NL Central behind division-leading Milwaukee, which has the majors' best record at 18-6.
"The team's rolling right now and just kind of riding the waves, going with it, and playing outstanding ball," Wood said.
But the win was overshadowed somewhat by the injury to Segura, adding to what's already been a tough start of the season. Segura, who was hitting .239, also missed the last two weeks of spring training with sore right shoulder.
Braun has also had somewhat of a tricky start after returning to the lineup this season following a 65-game doping suspension. Braun is hitting .318, but he's also been dealing with a lingering right hand injury that carried over from last year.
Chicago placed struggling reliever Jose Veras on the 15-day disabled list with a strained left oblique. RHP Brian Schlitter was recalled from Triple-A Iowa, and arrived in time for the game. Veras had a 15.88 ERA and blew both of his save opportunities. ... The Cubs have lost seven of eight to Milwaukee dating to last season. ... Rodriguez picked up his 315th save, three behind Rick Aguilera for 17th place on the career list. ... Chicago will try to avoid a sweep by sending Jason Hammel (3-1) to mound Sunday against Wily Peralta (3-0).