There's a chance that McCann's vision has changed since he underwent Lasik surgery at the conclusion of the 2007 season. If this is the case, the Braves' All-Star catcher would need to undergo the corrective procedure again and possibly be sidelined for at least a week.
But before putting himself in a position where he might need to go on the disabled list, McCann has attempted a handful of other corrective procedures. After finding dry spots on the 25-year-old catcher's left eye last week, an eye doctor in Atlanta suggested the use of a corrective contact lens.
"When he tested my vision, it's definitely off a little bit," McCann said. "It needs to be corrected a little bit. But at the same time, I've got a couple of dry spots on my eye, and that could be causing this. So you don't want to go in and repeat the surgery when you don't need to."
With the lens providing no improvement, McCann began utilizing an antibiotic ointment on Saturday night. While the ointment might provide a long-term solution, it's immediate effect was increased blurred vision that prevented the catcher from starting Sunday afternoon's series finale against the Pirates and Monday's game at Washington.
"It's going to be a day-to-day thing," McCann said. "It could clear up tomorrow. But at the same time, it might not. ... It could be as early as tomorrow and could be as late as... I don't know."
Along with providing blurred vision, McCann's left eye has also produced an uncomfortable dry feeling. But while utilizing drops at least six times a day, he hasn't experienced any improvement.
"It's a trial-and-error thing," McCann said. "We're going to try to get to the bottom of this."
While recording six hits, including five for extra bases, during his first 15 at-bats, McCann thought he was simply having trouble adjusting to the big stadium bright lights that he hadn't seen since the conclusion of the World Baseball Classic.
But with just one hit in his past 20 at-bats, McCann has confirmed that he definitely needs to do something about this unknown ailment that is causing him more problems during night games.
"We'll know more when I get under the lights for a night game," McCann said. "So Monday night, I'll have more answers for you."
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.