The Orioles were expected to announce the signing today of closer Grant Balfour to a two-year contract, but an issue has arisen concerning his physical, according to multiple industry sources.

Balfour agreed Tuesday to a two-year, $15 million contract that included $500,000 deferred over each of the next two seasons, and the Orioles were expected to introduce him Friday morning at a press conference at Camden Yards. However, there’s been an undisclosed glitch related to his physical and the deal is in serious jeopardy.

The results of the physical have come back to the Orioles. The failure to announce his signing isn’t due to any sort of delay.

A source said there are some issues that “need to be resolved.” Executive vice president Dan Duquette couldn’t be reached for comment, but he’s expected to address them on Friday.

Update: The issue at least partly involves Balfour’s right shoulder, according to a source. Something was revealed on the X-rays that must have raised concerns. But is there more to the story? Stay tuned.

Balfour, who turns 36 later this month, was supposed to replace Jim Johnson as the club’s ninth-inning specialist. The Orioles traded Johnson to the Athletics on Dec. 2 for infielder Jemile Weeks and a player to be named, who turned out to be catcher David Freitas, a former Nationals prospect.

John Axford’s one-year, $4.5 million deal with the Indians became official earlier today, and he seemed to be the club’s second choice behind Balfour. Joaquin Benoit, another closer who interested the Orioles, agreed to a two-year, $15.5 million deal with the Padres.

Fernando Rodney and Chris Perez remain on the market if the Orioles don’t sign Balfour. They’ve checked the medical records of former Red Sox relievers Joel Hanrahan and Andrew Bailey, who won’t be ready on opening day while recovering from their respective surgeries.

The Phillies are shopping Jonathan Papelbon, who’s entering the third year of his four-year, $50 millioin contract. Duquette told reporters that he didn’t speak to them at the Winter Meetings.

Balfour reportedly had a higher-paying offer from another club before agreeing to terms with the Orioles, believed to be two years with a vesting option. The Orioles considered including a vesting option in their proposal, but got a deal done without one.

Now, it’s not likely to become official unless there’s a major shift over the next 24 hours.

Balfour has converted 62 of 67 save opportunities over the past two seasons. He’s posted ERAs of 2.28, 2.47, 2.53 and 2.59 over the last four seasons.

Balfour registered 38 saves for the Athletics this year and allowed 48 hits, walked 27 and struck out 72 in 62 2/3 innings.

Back in December 1998, the Orioles agreed to terms with reliever Xavier Hernandez on a two-year, $2.5 million contract, but the right-hander’s physical revealed a torn rotator cuff and the deal was voided.

The Orioles reached agreement with starter Aaron Sele on a four-year, $29 million prior to the 2000 season, but the deal fell apart due to concerns over the results of his physical. Sele signed a two-year, $15 million contract with the Mariners.