Berken, who was claimed off waivers by Chicago on Sept. 7, will toe the rubber Wednesday night at Coors Field in search of his first win in a Cubs uniform. The righty has pitched well in each of his first two starts with the Cubs, allowing just two earned runs in 10 innings -- a 1.80 ERA -- while striking out seven and walking three.
In his last outing he worked six scoreless innings and held the Reds to two hits. Although he didn't come away with the win, he commanded his pitches well and worked ahead in the count.
"It's one start," Berken said afterward. "I think it's important for me to build off this and put another one together after this one. There's always something to prove. I'm never comfortable or going to assume anything. For me, it's a matter of putting together a couple more good starts and going into the offseason on a positive note.
"By no means is it time to ease off or sit back. It's time to get after it even more and get ready for the next start."
While Berken hopes to build off a strong outing Wednesday night in Denver, Rockies lefty Drew Pomeranz (1-9) looks to snap a 13-start winless streak and extend Colorado's win streak to three games.
Pomeranz had a rough time his last outing, as he fell behind in the count often and walked a season-high five batters against the D-backs, who tagged him for four runs. The lefty didn't factor into the decision, but he struggled to locate his fastball, causing him to throw 85 pitches despite working just three innings.
Since notching his lone win of the season just before the All-Star break -- 6 1/3 scoreless innings against the Nats on July 6 -- Pomeranz has struggled in the second half, going 0-6 with a 6.84 ERA, raising his season ERA from 3.06 to 5.30.
"I think I'm trying to do too much out there, trying to think about making too good a pitch, instead of just making pitches," Pomeranz said. "I'm trying to make every pitch perfect instead of throwing a strike or hitting a corner."
Cubs: Barney closing in on Polanco
After another errorless game Tuesday, second baseman Darwin Barney has gone 139 consecutive games without committing an error. Barney is now two games shy of tying Placido Polanco's Major League record for consecutive errorless games by a second baseman.
Batting leadoff on Tuesday for the first time this season, Dave Sappelt showed off what he could do given the opportunity. Sappelt led off the game with his first career home run and finished the night 2-for-4.
"Since he's been here, he's shown us some really good at-bats and shown the ability to hit a fastball and get his walks as well," Cubs manager Dale Sveum said before Tuesday's game. "I thought I'd stick him in that leadoff spot and see what happens."
Rockies: CarGo still day to day
Left fielder Carlos Gonzalez was out of the lineup for Tuesday's series opener due to a tight left hamstring. Gonzalez underwent an MRI on Monday, and it revealed no structural damage. He remains day to day.
Center fielder Dexter Fowler also missed Tuesday's series opener due to tendinitis in his right wrist, although manager Jim Tracy said Fowler was available off the bench.
Cubs reliever Carlos Marmol needs one more appearance to reach 450 games pitched for the Cubs and pass Don Elston for third most in franchise history.
Rockies rookie catcher Wilin Rosario has multiple hits in five straight games.