Ruiz underwent treatment following Friday's contest with head athletic trainer Scott Sheridan and downplayed the severity of the injury.
"I had an oblique problem in Colorado last year -- or a couple years ago -- and I know how it feels," said Ruiz, who missed 21 days in 2009 with an oblique strain. "I think this is more like a cramp -- you know, when you pull a hamstring. This is more like a cramp. That's what I feel. They want to make sure that I'm OK. Today, when I woke up, maybe I was a little sore. But I feel good. I'm ready to go. We'll see how it goes."
Despite Ruiz calling the injury a cramp, the team is classifying it as a strain and will require Ruiz to be examined further in the coming days.
"We will evaluate him when we get back to Philadelphia," said assistant general manager Scott Proefrock.
The positive news is that Ruiz took batting practice on Saturday and is not certain to land on the disabled list.
Backup catcher Brian Schneider, who entered for Ruiz after he left Friday's game, got the start behind the dish on Saturday and was penciled into the eighth spot in the order.
As insurance, the Phillies recalled catcher Erik Kratz from Triple-A Lehigh Valley. To make to room for Kratz on the 25-man roster, Philadelphia optioned right-handed reliever B.J. Rosenberg to Lehigh Valley.