"Sarwan was hit by a delivery from Pakistani fast bowler Umar Gul and the X-ray report shows a hairline fracture on the instep of his right foot which is now placed in a cast," West Indian media manager Imran Khan told reporters on Friday.
Pakistan and the West Indies play the first of five one-day matches in Rawalpindi on Dec 5.
The 26-year-old Guyanese will fly back to the West Indies in the next couple of days, said Khan.
Sarwan only returned to the West Indies team in the third Test after being left out of the second Test at Multan due to poor batting form.
He was batting on 35 in the pre-lunch session in the third Test when Gul's yorker hit him on the foot. He returned to the pavilion and went to hospital for an X-ray.
The West Indies next play a four-match one-day series in India in mid-January.