You really think these guys don't get a full opthalmological exam from the team's eye doctor (which happens to be Willis) every year?
I think this is just a young/inexperienced player whose technique and ability to read balls coming off MLB hitters in MLB parks and a variety of light and weather conditions is still a work in progress.
The only reason anyone is concerned/surprised or viewing this as anything other than a small sample/early career struggle is because they were awarding him the Gold Glove for small sample/early career overachievement last September.
You could certainly still make the case for sending him to AAA, Pache is probably an equivalent player to Rojas at this time, and then they could address that roster spot for the next couple of months before bringing him back up and/or trading for a bench bat upgrade.