The 24-year-old was stretchered off the field during the Saints' 4-1 defeat to Manchester City this afternoon after landing awkwardly, prompting doubts over his selection for England's World Cup campaign.
The club's medical staff placed the striker's right leg in a knee brace and Pochettino says that the full extent of the damage will not be revealed until returning to the South Coast.
Speaking to reporters at full time, the Argentine said: "I don't know how Jay Rodriguez is. It's not looking good but we'll be assessing it in Southampton."
Rodriguez, who made his Three Lions debut in November last year, has scored 15 goals for Southampton this season.