Granted, Jake Arrieta isn't the same pitcher he was in 2015 when he won the NL Cy Young Award. Arrieta is 6-5 with a 4.64 ERA. His fastball velocity is down to 91.8 mph from 93.8 last year. 

But Arrieta still rates a strong edge against Marlins starter Jeff Locke and the defending world champions still are much superior to the Marlins. 

Arrieta has a good track record versus Miami with a 1.42 ERA in three career starts. He'll be helped pitching at Marlins Park, a pitcher's park. 

Locke may be the worst player ever to appear in an All-Star game. He's 0-2 with a 4.58 in four starts this season after coming off the DL. The southpaw is 1-5 lifetime against the Cubs with a 5.98 ERA in 13 appearances, including 11 starts. 

Wildness is an issue with Locke and the Cubs draw the most walks versus lefties of any team. It's one of the reasons why the Cubs have won 63 percent of their games against lefty starters this season.