"That's as good as he's been all year," Phillies manager Pete Mackanin said.
Eickhoff struck out seven batters through four innings. He struck out the side in the fourth, giving him six strikeouts in seven at-bats.
It helped that he showed the Cubs a bit of a different look.
Eickhoff threw a career-high 28 sliders. His previous high had been 25, which came in his previous start. He struck out three batters on the pitch Tuesday. He had struck out just five batters on sliders the entire season entering the night.
Eickhoff's best pitch is his curveball. He entered the game with 40 strikeouts on that pitch. But the slider was working well Tuesday, so he kept with it.
It has been a conscious effort on his part. It began a few starts ago following a conversation with Phillies pitching coach Bob McClure, and another talk with Phillies broadcaster Larry Andersen. Eickhoff threw his slider just 6.1 percent of the time in April and 14 percent of the time in May. That number is up to 26.6 percent through two June starts.
"That was kind of the spark," Eickhoff said. "To key them off my fastball and curveball. It's a huge thing to think about, just a third pitch for the hitters."
Todd Zolecki has covered the Phillies since 2003, and for MLB.com since 2009. Read his Phillies blog The Zo Zone, follow him on Twitter and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.