Shorts left Friday's opening training camp practice early with what he said was tightness, but further tests revealed a Grade 2 strain, which surprised Shorts.
"I wasn't expecting to hear that," he said. "We've got a plan [for] how we're going to attack this situation. We're going to do what we've got to do to get back."
Shorts missed most of OTAs and minicamp with tightness in his left calf, and the latest injury raises concerns about his ability to stay healthy. He has missed 11 games in three seasons for various injuries, and played through a painful shoulder injury last season, landing on injured reserve on Dec. 16 with a sports hernia.
"Can't catch a break right now," said Shorts, who suffered his injury during a passing drill. "You learn to deal with it. It's always tough when back-to-back injuries happen to you. I'm not going to lie to you: It's difficult. But I'm going to stay positive about it. Being frustrated is not going to do anything for me so I'm going to stay positive and attack this rehab and get this thing right."
Jaguars coach Gus Bradley said it helps that Shorts is familiar with the offense and they know what to expect from him on the field, so there's no rush for him to return.
"We trust Cecil so much as far as being mentally ready," Bradley said. "[He] knows what to do. We'll have enough time so we'll be okay."
Shorts is entering the final season of his rookie contract. He has 123 receptions for 1,786 yards and 11 touchdowns in his first three seasons, including 66 for 777 yards and three touchdowns last season.