The 6-foot-3, 210-pound Robinson suffered the injury on a long pass play late in last Wednesday's OTA. He did not participate in Thursday's workout because he attended the NFLPA's rookie premiere. The Jaguars have OTAs on Tuesday and Thursday and four more next week before a mandatory minicamp June 17-19.
Coach Gus Bradley said he's not sure when Robinson, one of two receivers the Jaguars drafted in the second round, will be able to return.
"We'll see how it goes," he said. "It was unfortunate. Long pass and he tweaked it a little bit. He's getting treatment. He's doing things right. We'll see how fast he comes along."
Robinson caught 177 passes for 2,474 yards and 17 touchdowns in three seasons at Penn State. He had 97 receptions for 1,432 yards and six touchdowns in 2013 despite playing with a freshman quarterback.
The Jaguars' other second-round draft pick, receiver Marqise Lee, missed Monday's OTA with an ankle injury, and a team spokesman said Lee is listed as day-to-day. Lee caught 248 passes for 3,655 yards and 29 touchdowns in three seasons at USC.