Ryan has been on the disabled list with left trapezius tightness after appearing in six games this season.
"[The MRI] came back really clean," Arnsberg said. "No really eye-opening things. There was a little bit of inflammation up in the trap. That could even be from the deep friction massages he has been getting. They are going to give him seven days [from Wednesday] of no-throw. He'll be there two or three days and then meet us back in Toronto. They just want to let it tame itself down and then we'll go back to the drawing board."
In other pitching injury updates, Arnsberg said left-hander Ricky Romero (strained right oblique) played catch on Wednesday and felt fine.
"We'll back him up 60-75-90 feet on Thursday," Arnsberg said. "Eventually, he'll go back to 120 feet and then go to bullpen work from there. He's probably a week away from really being able to throw with a little bit of vengeance with the arm coming downhill. He'll do it in increments." Right-hander Shaun Marcum, recovering from Tommy John elbow ligament transplant surgery, is scheduled to throw a fastball/changeup bullpen session on Thursday. "We won't spin the ball off the mound at all," Arnsberg said. "That will be down the road a little bit. He'll go 35 pitches."
Robert Falkoff is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.