With Thairo Estrada slumping, could SF Giants shake up middle infield?

DENVER — Walking into the visitors’ clubhouse Sunday morning, Tyler Fitzgerald and Brett Wisely couldn’t help but smile when they saw the Giants’ lineup card. It featured the pair of streaking rookies up the middle, with the slumping Thairo Estrada taking a seat.

“We saw it this morning and we were both pretty excited about it,” Fitzgerald said. “We love Thairo, obviously, but it’s just someone that I’ve played with in the minor leagues. It’s fun and it’s pretty cool to see. It’s kind of...