"He came out [Monday] and did some of the drills, and we just couldn't get him to see anybody today," Reds manager Jerry Narron said. "With all the pain he had this past weekend, we just thought it was best to get him examined and see what the doctor says, and go from there."
Because Hamilton also came down with a stomach ailment last month that caused him to miss a few games, the club is sending him to see a specialist in gastric disorders on Wednesday. But the recommendation from team medical director Dr. Tim Kremchek was not to wait for the outcome before putting him on the DL.
Reds general manager Wayne Krivsky decided to heed Kremchek's advice.
"If it wasn't the second time he had something similar, it might have been a different story," Krivsky said. "But this is the second time in a month. If you consider everything Josh has gone through since February 1 -- and probably back to the winter after the Rule 5 Draft -- to prepare to come into the big leagues, he's been getting after it pretty good. I'm sure it's been a shock to his system, like it would be to anybody. It just seemed to make sense to take a step back and let him get some rest."
If Hamilton isn't diagnosed with anything serious on Wednesday, he could be sent on a Minor League rehabilitation assignment in the next few days. He is eligible to be activated from the DL on June 3 while the Reds are visiting Colorado.
"We could have waited, but we'd be playing kind of short," Krivsky said. "We wouldn't have been able to back date him [if he appeared in a game]. Based on what Doc said last night, he felt strongly this was a time for him to take a step back, and get his system right and his body strong again."
In 37 games this season, Hamilton is batting .261 with eight home runs and 18 RBIs. One of the surprise stories of 2007, he made the Reds with a spectacular Spring Training after a near four-year absence from baseball because of injuries and suspensions for drug use.
In mid-April, Hamilton took over as the starting center-field role from Ryan Freel and went on to become the National League Rookie of the Month.
With Hamilton out, Freel will return to center field, while Encarnacion will man third base.