PITTSBURGH — Konnor Griffin has had his struggles at the plate early in his MLB career, but recently has found some success swinging the bat. Griffin has been excellent for the Pirates the past five games, slashing .389/.421/.722 for an OPS of 1.143, which includes seven hits in 18 at-bats, his first two home runs, five RBI and two stolen bases. He's also had a good two-plus weeks as of late from the plate, slashing .273/.310/.436 for an OPS of .747 in his past 15 games, with 15 hits in 55 at-bats, a double, a triple and nine RBI. Griffin only just turned 20 years old, but as he closes in on his first full month in the major leagues, it's a good sign for the Pirates that he's improving offensively. Griffin Finding Success Against Higher Velocity Pitches The adjustment from the minor leagues to MLB is massive for any player, particularly one as young as Griffin.…