There isn't much info.
Only a routine physical exam stood between them and an official deal.
However, executive vice president Dan Duquette stated that Balfour's performance on the exam didn't meet Baltimore's standards, according to Kubatko:
"The Orioles were disappointed that we couldn't complete a contract with Grant Balfour," Duquette said. "The reason is the club's not satisfied with the results of the physical exam.
"We would never say never or close the door, but we're turning our attention elsewhere for now to look at some other options to try to staff our team and try to build a contending team for 2014."
Per Kubatko, Duquette wants "to protect confidentiality," so we don't know which of Balfour's bodily regions is damaged, nor can we infer what the severity of the injury is.
from susan slusser:
Grant Balfour is mystified by #Orioles backing out of deal because of health concerns, tells me he is "100 percent fine."
More Balfour: "My shoulder is fine, everything is fine. I'm ready to come out there in the ninth inning, do what I do."
also, i thought this was interesting. this is from 2012.
The Oakland Athletics used him on five consecutive days from Sept. 29 to Oct. 3 in order to ensure an AL West title. In each of those last four appearances, he completed a full inning on zero days' rest. That's a streak matched by only 10 pitchers so far this millennium!