Extra bases

Jake Arrieta, slowed this spring after feeling some tightness in his right shoulder, still has yet to throw off a mound in camp. The right-hander was projected as the fourth starter but most likely will not be ready by Opening Day.

• Renteria isn't wasting any time. Infielders, including first baseman Anthony Rizzo and second baseman Darwin Barney, were on the field early Thursday for extra work.

• If fans see extra players at the spring facility this week, it's because there are some Minor League players taking part in a mini-camp. Among those participating are top prospects third baseman Jeimer Candelario and outfielder Eloy Jimenez.

Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.