Tonight at 8 p.m. ET on ESPN, the St. Louis Cardinals will look to win for the fifth time in seven games at Wrigley Field this season when they take on the Chicago Cubs. To do so, the Cardinals will need to get starting pitcher Mike Leake back on track.

After a pair of dominating starts in mid-July (2-0, 1.38 ERA, 21 K, 0 BB), Leake recently has struggled. Over his past four starts, Leake is 1-2 with an ERA of 9.00, allowing a .359 batting average.

So what changed over Leake's past four starts?

Pitch selection not the same

In Leake's starts on July 10 and 17, 50 percent of his pitches were sliders or cutters, and 33 percent were sinkers. Over his past four starts, he's relied more on his sinker, which he’s thrown on 45 percent of his pitches, compared to 36 percent for his slider/cutter.

The result: After hitters missed on 35 percent of swings against Leake in those two July starts, hitters have missed on only 16 percent of swings in his last pour starts.

Can the Cubs be the cure?

As unusual as it may appear, especially when discussing the team with the best record in baseball, the Cubs could be the right team for Leake to find his rhythm again.

In his career, Leake is 9-3 against the Cubs with a 3.18 ERA. He has pitched into the sixth inning in 19 of his 20 lifetime starts against the Cubs, and he has held Chicago to a .243 batting average.

Against the rest of the league, Leake is five games over .500 (63-58), with a 4.08 ERA and a .270 opponent batting average.

The bad news for Cardinals fans: Leake took a loss in his only start against the Cubs this season. However, that start came back in April, and Leake's numbers in that game were solid (7 IP, 3 ER, 6 H, 6 K, BB).

Coincidentally, the opposing starting pitcher that day was John Lackey, tonight's starter for the Cubs. Lackey fired seven shutout innings, allowing four hits with 11 strikeouts.