He will know more Tuesday. He strained his right calf in the ninth inning Monday in a 6-3 loss to the Brewers in 12 innings at Citizens Bank Park. Romero limped through the Phillies' clubhouse afterward.
"Probably, probably some time," said Romero, asked if he expected to be placed on the DL. "I don't know how long, but hopefully 15 days or so."
Romero recorded the first two outs of the ninth, when Brewers center fielder Carlos Gomez reached on an infield single. Romero hopped off the mound after throwing the pitch before dropping to the turf in pain.
"I was trying to push off the leg, and it kind of gave out on me," Romero said. "I knew something was wrong."
Romero, who will have a MRI on Tuesday, is 0-0 with a 3.86 ERA in seven appearances this season.
"I don't know what else could happen," Romero said. "This is just ridiculous. At least my arm is good."
Possible replacements for Romero, if the Phillies place him on the DL, include right-hander Michael Stutes and left-hander Mike Zagurski.