O'Brien has impressed with his bat during the early days of camp, the Diamondbacks' official site reports. The Arizona front office will continue to develop O'Brien as a catcher, where his defense is still a work in progress. Without an established option in camp positioned to handle the bulk of the playing time, the young backstop will have an opportunity to secure the job in a competition with the likes of Tuffy Gosewisch and Gerald Laird this spring.