Diaz went 1-for-2 in Montreal on Saturday as a minor-league callup.
He hit .286 in 35 spring at-bats. Given the likelihood of injury to Pittsburgh's top two catchers, Francisco Cervelli and Chris Stewart, there's a good chance Diaz could see considerable playing time in 2017. The 26-year-old features an unexciting slash line of .258/.323/.362 in eight minor-league seasons but batted .312 and .271 in 2014 and 2015, respectively, before getting hurt last year.