In the top of the seventh inning on opening day, A’s infielder Tony Kemp hit a dribbler down the left-field line. Bryson Stott scooped it up bare-handed and fired it to first base, throwing it past Rhys Hoskins. Stephen Vogt scored from second base, and Stott was charged with an error.

Stott’s blunder was just the latest of a series of miscues by the rookie third baseman. Earlier in the inning, he retrieved a ball hit by Elvis Andrus and threw it toward Andrus as he was running to the bag. Hoskins couldn’t come up with it and was charged with an error.

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Three at-bats later, Christian Pache knocked a grounder to Stott’s right side, for which he dove and narrowly missed.

Nick Castellanos watched all of this from the dugout but didn’t feel trepidation for his young teammate. In Stott, he saw a player who wasn’t afraid to dive for a ball or make a challenging throw. It was a quality Castellanos felt he lacked while he was playing third base earlier in his career with the Detroit Tigers.

After the game, Castellanos approached Stott in the clubhouse.

“He said when he was playing third, he would keep himself up at night looking at the lineup, looking at which guys were going to hit him grounders,” Stott said. “And that’s where he went wrong at third. He was thinking of the plays he was going to mess up and not the ones he was going to make. He said he wants me to throw those balls every time and go get the ones I think I can get and be an athlete and just go do it.

“He told me to relax. He said, ‘I didn’t relax, obviously, and that’s why I’m in left field.’”

Castellanos played third base throughout his minor league career and for four seasons with the Tigers. He committed 54 errors over 527 major league games and posted a minus-45 defensive runs saved (DRS) over that span. He believes the fear he felt while playing the position is the reason he’s manning the outfield now.

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“I was playing timid,” Castellanos said. “I was afraid to mess up because you don’t want to mess up. I know for a young kid, it’s easy to be like, ‘[Expletive], I already started the year with two mistakes.’ But it doesn’t matter. And I really applaud him because the next plays that he made, which weren’t routine plays, he made effortlessly.

“I told him that the errors he made were aggressive errors. He’s going to make the play. What you don’t want to happen is for a player to start shying away from wanting to make great plays because he’s scared of making mistakes.”

The message resonated with Stott, who sees Castellanos’ experience as a cautionary tale.

“He’s someone who admits where he went wrong,” Stott said. “He doesn’t want to see someone else go the route that he did. He enjoys playing third. He takes grounders with me all the time. To see someone who loves playing the infield have to go to the outfield because of that no-mistake world he was living in … he obviously doesn’t want that happen to anyone else. So he helps me out as much as he can.”

Stott said if he thinks he can get a runner out, he’ll always make a throw from third base, no matter how daunting it might seem. He said if a ball is veering toward his right or left, he’ll make those diving catches, too. The goal for the rookie is to play defense fearlessly. And Castellanos doesn’t doubt Stott is capable of doing that.

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“You can see the freedom that he has when he’s going after the baseball,” Castellanos said. “You can see it. It’s hard to explain, but you can tell when someone is smooth and confident, and you can tell when someone is rigid and unsure.

“He’s a stud. He gets it.”