X-rays were negative on Souza, but he was sore on Wednesday and wasn't sure about his status going forward.
"Right now it just feels sore," Souza said. "In that specific moment [of the injury] it felt like I literally had no control of where it was going. I don't think it's anything too crazy right now. Tomorrow I'll probably have a little better feel and I'll have a little more of an update."
Decker was hitting .233 with five home runs and 14 RBIs for the Bulls this season.
He entered Wednesday's game in the eighth inning as a pinch-hitter and went 0-for-3 in the Rays' 3-2 victory in 13 innings over the Mariners.
"As far as Jaff Decker coming up, we're excited for him, he had a great spring with us," Rays manager Kevin Cash said. "Hopefully he can get hot like he was in Spring Training, because he did a lot of good things.
"And the thought was behind that, we know Souza's pretty banged up, a little sore. We'll monitor him day to day now, and make some decisions as we go and as he responds."
Eveland was 0-1 with a 7.56 ERA in 21 games for the Rays this season.
"Kind of a grind for Dana, [we] appreciated the way he went about his business," Cash said. "Just wasn't working out. Hopefully, if he gets an opportunity in the big leagues, great for him. If not, potentially we'll see him in Durham, and he can iron some things out. We still think that, with his breaking ball, it's something that could help us at some point."
The Rays will still need to make a roster move so Blake Snell can be activated to start the final game of their three-game series against the Mariners on Thursday. Given the Rays' cautious approach to injuries, fair speculation would be that Souza goes on the DL.
Bill Chastain has covered the Rays for MLB.com since 2005. This story was not subject to the approval of Major League Baseball or its clubs.