PHOENIX -- While Chad Billingsley was suiting up before throwing a workmanlike six innings in a Minor League game on Tuesday, Hong-Chih Kuo was icing his arm nearby.

Billingsley was the only Dodger required to be at Camelback Ranch-Glendale on what was scheduled to be a day off for the club, but Kuo's presence for treatment was further evidence that all is not right with the left-hander, who might not make the Opening Day roster.

Of course, all is never right with an elbow that has been operated on four times. But Kuo experienced more tenderness following an impressive 1-2-3 inning on Friday night, and he hasn't played catch since. That outing came after the cancellation of what would have been a triumphant one-inning start in his native Taiwan, scratched because his elbow was sore after his only other appearance, when he struck out two of the three batters he faced.

In fact, Kuo has pitched in only two games this spring, 10 days apart, retiring all six batters but coming up sore both times. By comparison, Jonathon Broxton and George Sherrill have made six appearances each in either a Major or Minor League game.

Kuo appeared in seven games last spring but didn't get through the first month of the season before landing on the disabled list, where he stayed for three months because his tender elbow led to a mysterious case of the yips.

So, with Kuo's status uncertain, and the only thing definite about the status of Ronald Belisario being that he won't be ready (or possibly even in the country) on Opening Day, the bullpen has some issues. James McDonald, effective in middle relief last season, has already been sent down. Shaky springs by Sherrill and Ramon Troncoso have added to the murky equation, although both have histories of flipping the switch when the regular season starts.

Nonetheless, the bullpen was probably the key weapon in the Dodgers' success the past two seasons, and if the relief corps is more vulnerable as this season opens, starting pitchers such as Billingsley will need to carry a greater load.

With that in mind, Billingsley stretched out to 83 pitches and six innings in a Triple-A game against the Indians on Tuesday. He allowed three hits (two of them home runs), struck out three, walked one and hit a batter.

"My fastball felt great all day," said Billingsley. "My off-speed pitches weren't quite there the first few innings, but later on I got on top of the ball, and my curve and cutter were a little more efficient."

Billingsley has been pleased with the mechanical adjustments he made since experiencing a second-half fade last season after an All-Star first half.

"His delivery line is better, he's standing a little taller," said pitching coach Rick Honeycutt, who also gave up his day off to oversee Billingsley. "He had been getting across his line, falling to the third-base side early, and it affected his line. He had to try to get the ball back across, and it flattened out. That left him with more work than he had to be doing."

Among the batters Billingsley faced was catcher Carlos Santana, who has become one of the best prospects in baseball after being traded by the Dodgers to the Indians in the Casey Blake deal of 2008. Santana struck out and grounded out against Billingsley.