"We were hoping that [the flexor tendon] was the main part of the injury. It's a little less severe," Luebke said. "We did some X-rays and it showed something a little different. We still don't know exactly what's going on. The symptoms are all kind of pointing a certain way [to possible ligament damage]."
Luebke said he had previously never missed a start during his entire career.
"One of the things we enjoy doing is playing and being out there every fifth day, and to know there's a chance I might not be able to do that for a while is kind of disheartening," Luebke said. "But that's part of the game. I don't have to look around too far in this clubhouse to see some guys who are going through some stuff, too. You can't really feel too sorry for yourself. You have to do what you got to do."
If Luebke needs Tommy John surgery, he would likely be out for a year.
"A lot of worse things have happened. If it does come to that, the success rate, they're getting real good at it," Luebke said.
Manager Bud Black said Luebke continues to rest the elbow and receive treatment.
"As of now, [there's] no definitive plan as far as a rehab situation. [We're] still plotting a course of action," Black said.
Luebke joined fellow starters Dustin Moseley (shoulder) and Tim Stauffer (elbow) on the disabled list. Moseley is expected to be out for the season following shoulder surgery. Stauffer is expected to make one more rehabilitation start on Wednesday with either high Class A Lake Elsinore or Triple-A Tucson in New Orleans before he comes off the disabled list.
Luebke first felt discomfort in his elbow in the fourth inning of his last start against the Giants.
Luebke said his MRI exams during Spring Training revealed good results. In March, Luebke signed a contract extension that will guarantee him $12 million and could keep him with the Padres through 2017. He is 3-1 with a 2.61 ERA.
"I've been lucky," Luebke said. "Twenty-seven years of playing ball, I never really had to miss a start or miss anything."