In addition to bunting, Roberts took cuts from both sides of the plate, and he was encouraged with the results from Sunday's workout.
"Any time you are coming off of any type of injury, that psychological part is as much as the physical part," he said.
"It got better. The physical confidence as well as the psychological part ... the more you [take swings], the more confidence you get and the more effort you are able to put in."
The 32-year-old Roberts began experiencing nagging back spasms during his offseason workouts at the Athletes' Performance Institute in Arizona, and was originally misdiagnosed with kidney stones before doctors found the herniated disc a week later.
Roberts said on Tuesday that he had hoped to be able to swing a bat against live pitching within the next week. Prior to Sunday's workout, the Orioles second baseman had been a regular fixture at fielding practice and in the cages, and was only limited in swinging the bat during BP.
"That's the last phase, start hitting live," manager Dave Trembley said of Roberts' program. "So, it was good to get that started."
2010 Spring Training - null
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With the Orioles set to play an intrasquad game on Monday and open Grapefruit League play against the Tampa Bay Rays on Wednesday, the timetable for Roberts' spring debut is still undecided.
"I don't know [when Roberts will get in games]," Trembley said. "I will wait until I see what [head athletic trainer Richard Bancells] tells me, what [Roberts] tells me. I can't put a timeframe on it."
For now, Roberts said the plan is to slowly increase his workload and intensity, and try to limit the stopping and starting action that often results from waiting around in between turns at the plate.
"I don't think I'm going to start hacking off pitchers throwing 95 [mph] yet," Roberts said. "But we will increase with the batting practice and the intensity and maybe a few more swings, as well."
One of Baltimore's most consistent players, Roberts hit .283 with 16 homers and 56 doubles last year, breaking Lance Berkman's record for the most doubles by a switch-hitter in a season.