It also leaves the D-backs with 31 players in camp, and they will need to get down to 25 by Sunday's 9 a.m. MST deadline to have the Opening Day roster finalized.
"This last three or four days are going to be very difficult," D-backs manager Chip Hale said. "These guys have busted their [butts] for me, our staff and our fans. It's just hard to do these last few moves."
Gosewisch was popular among the team's pitching staff for his work behind the plate. He spent nine years in the Minor Leagues before getting his first big league callup with the D-backs in 2013. Last season he opened the year as the team's starting catcher before suffering a season-ending knee injury May 27.
Gosewisch hit .143 (6-for-42) this spring. Herrmann, who was acquired from the Twins in November, hit .229 (8-for-35) and battled a hip flexor injury this spring. The D-backs toyed with the idea of keeping three catchers since Herrmann can also play both corner outfield and infield positions.
With Castillo, Herrmann, Paul Goldschmidt, Jake Lamb, Chris Owings, Jean Segura, Nick Ahmed, Phil Gosselin, David Peralta, A.J. Pollock and Yasmany Tomas seemingly on the team, that leaves two spots open.
Those left in camp fighting for those two spots are outfielders Rickie Weeks Jr., Socrates Brito, Peter O'Brien and Jason Bourgeois, along with infielder Brandon Drury.
On the pitching side of things, if Josh Collmenter starts the year as expected on the 15-day disabled list, then there are two bullpen spots to be filled, with Evan Marshall, Enrique Burgos, Jake Barrett and Silvino Bracho competing.
Steve Gilbert is a reporter for MLB.com. Follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.