"It got pretty tight there, that last batter," Griffin said after the 7-6 loss to the Blue Jays. "It felt more like a cramp early on in the game. Sometimes those come and you can just pitch through them, but it kept tightening more and more."
After getting through the first inning with just one baserunner allowed, Griffin soon found trouble in the second as he loaded the bases with no outs. Blue Jays second baseman Devon Travis quickly made him pay with a grand slam to left field, but Griffin didn't need attention from the training staff until after he struck out the next batter, Ezequiel Carrera, with an 0-2 curveball.
"That's when we noticed it," said Texas manager Jeff Banister. "[Jonathan] Lucroy saw it, I saw it."
Griffin did not feel anything in his rib area prior to the start, and said that he has not dealt with a similar injury in the past, so he initially believed that he might be dealing with a common muscle cramp that he could pitch through. It was when the feeling continued to impact his delivery and movement, however, that he knew it was likely something more.
Griffin is expected to stay with the team for the remainder of its time in Toronto and will undergo an MRI when the Rangers return to Texas for their series beginning on Monday against the Rays.
"It was uncomfortable," Griffin added. "I couldn't get to my extensions on the glove side as well as I wanted to because I couldn't pull through as much as I wanted to."
In a corresponding move, the Rangers have called up right-hander Dillon Gee. Texas has not committed to a plan for Griffin's rotation spot, but after Austin Bibens-Dirkx threw 84 pitches in relief on Friday, Gee's first task will be bullpen work.
"I think, situationally, Gee will go straight into the bullpen," Banister said.
Keegan Matheson is a reporter for MLB.com based in Toronto. This story was not subject to the approval of Major League Baseball or its clubs.