Joe Ryan underwent another examination and a magnetic resonance imaging test on Thursday as the Twins try to pinpoint exactly what's wrong with their pitching-rotation cornerstone and how long he might be unavailable.

"We were on the road [when the injury occurred Wednesday], so there's a lot we don't know yet," Derek Falvey, the Twins' president of baseball operations, said Thursday morning after addressing the Society for American Baseball Research's annual convention. "We'll see how he feels, what the images tell us and what the doctors think, and we'll figure out what happens next."

Falvey said the Twins are optimistic that Ryan's injury, initially diagnosed as triceps tightness, is relatively minor.

"At this stage, we don't know what to expect. But one good sign is that his postgame evaluation was pretty normal," Falvey said. "If you have a ligament tear or something of that nature, the evaluation will say there's point tenderness in a certain spot, in his elbow or whatever. His was all triceps-oriented, and more muscle tightness than a sudden pain."

Ryan, who has thrown a team-high 135 innings this season and owns a 3.60 ERA, threw four pitches in the third inning Wednesday at Wrigley Field before calling for head athletic trainer Nick Paparesta, and he was immediately removed from the game.

"It was awful. It was terrible to see that," Falvey said. "But Joe said the muscle had tightened up on him, and when he threw that last pitch, he felt it tighten even more."

The Twins, off today, open a six-day, seven-game homestand Friday with a doubleheader against the Guardians at Target Field.