MINNEAPOLIS — Catcher Kevan Smith played in 87 games and batted .283 with 30 RBI for the White Sox last season, enough, he thought, to keep him on the team for 2018.

Even after the Sox signed Welington Castillo to a multiyear deal as a free agent to be the No. 1 catcher, Smith thought he would be the No. 2 ahead of Omar Narvaez, but it wasn’t to be.

“It was certainly a shock,’’ Smith said Wednesday of opening the season at Class AAA Charlotte. “I thought last year was a strong showing on my end. But signing Welington and having a minor-league option left was not a good combination.’’

An even bigger shock would open a door for Smith — Castillo’s 80-game suspension for violating baseball’s drug policy May 24.

“I don’t think any of us saw that coming,’’ said Smith, 29, who was on the Charlotte disabled list with a sprained ankle. “But it’s one of those things where another window of opportunity opens up, and I’ll do all I can to take advantage of it.’’

After guiding Lucas Giolito, who had more than his share of rocky outings before Smith arrived this season, through a quality start in the second game of a doubleheader Tuesday, Smith caught five innings of two-run ball from Hector Santiago and followed a 1-for-4 night of solid contact with two straight sharp singles, including one in the middle of the Sox’ four-run sixth that carried them to a 5-2 victory against the Twins.

The Sox got one run on a wild pitch by reliever Ryan Pressly, two on a single by Tim Anderson and a fourth run on Adam Engel’s squeeze bunt. Anderson was 2-for-4 with three RBI, hiking his total to 25, and he got his 13th stolen base.

After Santiago, Bruce Rondon, Jace Fry, Nate Jones and Joakim Soria (second save in two nights, sixth of the season) combined for four scoreless innings of relief.

“Baby steps,’’ Santiago said. “We got a couple of guys still hurt, so for where we’re at, we’re playing pretty good baseball right now.’’

Santiago prefers starting, but if he goes to the bullpen when Carlos Rodon returns this weekend, he won’t complain “because I knew what I was coming into, coming into that role of long guy, starter, short guy [when he signed in the offseason]. It’s a rebuild, so you let the young guys get as much exposure as they can.”

For what it’s worth, the Sox (20-39) are 2-0 with Smith behind the plate.

“I don’t feel like I missed a heartbeat up here,” Smith said. “I’m comfortable with the staff; everyone was welcoming when I got here and excited to see me. It felt like I had been here all year.’’

Manager Rick Renteria stopped short of saying Smith would be Giolito’s “personal catcher,” but look for him to catch the right-hander, who has struggled with a 7.08 ERA. In seven starts, including six last season, Giolito has a 1.99 ERA with Smith behind the plate.

“We just kind of have a good feel for each other,’’ Giolito said. “Good communication throughout the game. He does a good job seeing when I start to get off-kilter with my mechanics here and there.’’

Smith is big on pregame preparation, studying hitters’ tendencies and trends. He said Giolito can overthink at times.

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“I told him, ‘I don’t want you to think about anything,’’’ said Smith, a former quarterback at Pitt. “‘Let me do the thinking for you. Just get as comfortable as possible, stay through baseballs and throw strikes.’

“I wasn’t scared to throw any pitch in any situation with him; that’s what he needs to do.’’

The Sox need to win Thursday to capture a second straight series for the first time.

“Our guys are really grinding, trying to control what they can,’’ Renteria said. “We’ve had some good ballgames over the last four or five days.’’