Koch gave up two runs on five hits while striking out six over five-plus innings Friday against the Dodgers.
Koch, who made 14 starts and five relief appearances in 2018, is widely expected to be part of the Diamondbacks' bullpen, Nick Piecoro of the Arizona Republic reports. The right-hander has posted a 3.18 ERA over 17 Cactus League innings. "I've been extremely impressed by what he's done," manager Torey Lovullo said. "You walk into camp and know you're competing, you're told you have to earn the spot, and when you do things like this it really stands out." Koch is out of options, so the Diamondbacks risk losing him if they want to send him down.