Javier Baez will get an extended opportunity to play shortstop with Addison Russell placed on the 10-day disabled list with a strained right foot.

“Obviously not good to lose Addy right now,” Baez said. “Just try to get used to playing shortstop and play as much as I can.”

Russell apparently had been feeling pain the last few days, though it was never noticeable in his running and the Cubs didn’t know how it happened.

“I was not aware of it,” manager Joe Maddon said. “I guess it has been ongoing, and he probably has kept it kind of quiet. I don’t even know if it (affected) those last couple of throws he made (in Thursday’s loss). But we just thought it was wise to get it settled down right now.”

Maddon said he hasn’t heard anything about Russell’s shoulder, which had bothered him in the past.

Left-hander Rob Zastryzny, aka “Rob-Z,” was called up from Triple-A Iowa because of the need for another arm Friday, though Tommy La Stella could be an option after Kyle Hendricks preserved the bullpen with seven innings in the 4-2 loss to the Nationals.

Dancing machines: The danceoff between the Cubs’ and Diamondbacks’ bullpens during Thursday’s rain delays made national news.

Hector Rondon brought masks for the Cubs’ relievers, but the D’backs one-upped them with routines including a pantomime bobsled and a pseudo bowling match with players as pins.

“I feel like they had that planned for the last three months of the season,” Mike Montgomery said. “They were synchronized. They were funny and on point. You have to give them props.”

Extra innings: The Cubs face an old friend Saturday in Edwin Jackson, one of President Theo Epstein’s rare free-agent mistakes since coming to Chicago. With Gio Gonzalez on paternity leave, Jackson will get the start against John Lackey. Nationals manager Dusty Baker also moved Max Scherzer back a day becasue of his neck issue. He will send top prospect Erick Fedde out to face Jon Lester in Sunday’s finale.