CHICAGO -- Gavin Floyd left Sunday's 4-3 rain-shortened victory over the Mariners at U.S. Cellular Field after two innings because of discomfort in his right elbow.
Floyd allowed one run on three hits, striking out one and walking one, while throwing 42 pitches. Hector Santiago, who was stretched out via three starts at Triple-A Charlotte during an Aug. 3-13 Minor League assignment, replaced Floyd and threw four innings covering 73 pitches.
Right elbow tendinitis previously put Floyd on the disabled list on July 17 (retroactive to July 8). He had gone 5-2 with a 3.17 ERA over his last 10 starts, including seven quality starts, although he only lasted 2 1/3 innings during a no-decision Monday against the Yankees.
According to Floyd, he will stay back in Chicago while the team travels to Baltimore and go through tests Monday that will include an MRI. Manager Robin Ventura all but ruled out Floyd from his start in Friday's series opener against the Tigers at Comerica Park.
"He would have to feel real good in the next couple days to be able to do that," said Ventura of Floyd's immediate return to the mound. "You would assume taking a guy out in the third inning, I would be hard-pressed to put him back in there a couple days later."
"I hope it's precautionary," Floyd said. "Tomorrow we are going to do what we need to do as far as testing and hopefully it's just the same thing. Just maybe a little break and something different and get back out there as soon as I can."
There was no sort of significant pain being felt by Floyd in the first inning. But when he sat down and went back out to the mound for the second inning, the pain went back to where it was before Floyd went on the disabled list in July.
"Obviously, I wanted to go back out [for the third], but it's one of those things that it can get worse," Floyd said. "It kind of started bothering me a little bit in the first inning, late in the first. And then the second inning, it really started to kind of affect me. I felt it every time I threw a breaking pitch or even a fastball a little bit."
If Floyd is lost for any significant amount of time, Santiago or Philip Humber could step into his rotation spot. Sixteen of Humber's 22 appearances this season have come as part of the starting rotation. The White Sox could rearrange the rotation on Wednesday or Thursday to put one of these hurlers against Baltimore, leaving Jake Peavy or Jose Quintana to open the series against the Tigers.
Santiago is prepared for his name to be called if needed.
"Humber started as a starter, and he's got more experience and has been in the league a lot longer than I have," Santiago said. "I'm saying he would have a better opportunity than I would. But if they give it to me, I'm ready for it."
Scott Merkin is a reporter for MLB.com. Read his blog, Merk's Works, and follow him on Twitter @scottmerkin. This story was not subject to the approval of Major League Baseball or its clubs.