Non-roster Invitees start their case for the Opening Day roster
The Diamondbacks have some NRIs in camp that could break the Opening Day roster. One is left-handed reliever Jose Castillo. Castillo once looked like a future bullpen ace for the division rival in 2018. In his rookie season, he pitched to a 3.29 ERA with a 34.7% K% and 8% walk rate in 38.1 innings. But he's pitched a mere two frames since then after countless injuries that have kept him out of play.
Castillo signed a minor league deal this off-season, and he's looked decent in his small Spring Training sample size. He has pitched two and two-thirds scoreless frames with three strikeouts. He has also not walked a single batter. However, he has sat 95.5 MPH with his four-seam fastball. The lefty could find himself with a spot in the D-Backs' bullpen if he continues to pitch well and keeps the velo up all pre-season.
Another NRI who is starting to make their case is catcher Tucker Barnhart. The second catcher role behind Gabriel Moreno is up for grabs. One of the players who could claim it is the veteran Barnhart who signed a minor league deal this off-season as well. Barnhart batted a horrible .202/.285/.257 with a 53 wRC+ for the Chicago Cubs. His only positives were his 9.8% walk rate in 123 plate appearances and his +4.3 framing runs.
Barnhart is getting a headstart to his candidacy as the team's secondary catcher as he's gone 2-3 with a walk. One of his two hits went for two bags. Other players currently in camp with the Diamondbacks who will also be competing for the second-string catcher role include Jose Herrera and Ronaldo Hernandez. Obviously, three at-bats is nothing to take super seriously, but it is something to keep an eye on as he has gotten off to a decent start.