“He heals pretty quickly for an old man,” Coach Ben Olsen said with a laugh.
De Rosario, who turns 35 next month, worked on the side during Monday’s practice and said afterward he was feeling better and would gauge his progress as the week unfolded.
United was off Wednesday and will resume workouts Thursday morning.
“We will have a good idea [of his status] tomorrow,” Olsen said, “but I expect him to be available” against the Red Bulls (1-3-2) in the second meeting between the rivals.
United (1-3-1) would welcome any attacking help. The club has scored just twice, been shut out three times and created few opportunities throughout the spring. Midfielders Nick DeLeon, John Thorrington and Lewis Neal remain out with injuries.