CHICAGO -- After Welington Castillo left Tuesday's 6-5 loss to the Rays with a right knee injury, manager Rick Renteria said he isn't worried about his veteran catcher. Renteria said Castillo had some soreness and is day to day.
But, being extra careful with their biggest free-agent acquisition of the winter, the White Sox on Wednesday sent Castillo for an MRI to confirm it's nothing serious.
"He's available to me today in an emergency," Renteria said. "I just figured, after we took him out yesterday, we'd give him a day today to take it easy, be available for me [Thursday] to start. I think it's just precautionary."
Castillo tweaked his knee on a throw down to second base on Tuesday, Renteria said, and was removed for pinch-hitter Omar Narvaez in the sixth inning. Renteria added Wednesday that Castillo had switched to metal cleats recently and one of his spikes got caught in the ground.
"To be honest, that was the first that I kind of heard of it," Renteria said. "Not sure why he switched to metal, but he's welcome to use the spikes that he needs to be able to feel comfortable out there on the field.
"We don't want to lose that guy. Big part of us."
Narvaez stepped in again for Wednesday's series finale, making his third start of the season. He went 1-for-4 in the White Sox 2-1 win.
After entering Tuesday's game, the 26-year-old Narvaez performed well -- despite going 0-for-2, he drew a walk and cranked a sharp line drive in the White Sox ninth-inning comeback attempt. Narvaez's exit velocity on that liner registered at 100.8 mph, per Statcast™, his hardest-hit ball of the young season. Narvaez also thew out Mallex Smith attempting to steal in the ninth.

As a role player, Narvaez said part of his preparation involves being ready for any situation. He added that he and Castillo have developed a good relationship and Castillo sharing his experiences has helped him improve his own game.
"We're pretty close," Narvaez said. "We help each other and whatever I see I tell him, whatever he sees he tells me. We're have a really great friendship going on right here, so if anything happens, we're gonna support each other."
Saladino healthy, hopes back issues behind him
Tyler Saladino's past two seasons have been abbreviated due to back injuries, but at the start of this season, he's feeling no problems.
Saladino received consecutive starts this week and went 2-for-3 with a double Tuesday, a good sign for the young infielder. Though Saladino said he'll need to keep an eye on the situation, he hasn't needed any extra exercises to stay loose.

"Just the same kind of stuff that we do in the offseason, stretching areas like core exercises and stuff like that," Saladino said. "I don't think back stuff ever really goes away, even if you do get it taken care of or whatever. In my experience, you still have to stay on top of it, so I feel good. Heck of a lot better than last year."
Saladino suffered a herniated disk in his back in 2016, cutting short a breakout year in which he hit .282/.315/.409 with eight home runs and 38 RBIs in 319 plate appearances. Last season, Saladino jammed a nerve in his back sliding into home and missed a month and a half.