Alex Cora didn’t mince words when discussing Triston Casas’ defense before Tuesday’s game.

“Inconsistent,” the Sox skipper said. “There’s a few things that we’re working on with him, and we believe he can be much better.”

Casas was even harder on himself.

“I only remember the games that it’s lost us,” he told the Herald of his defense. “It’s one of those things, you do 10 things good and then one thing bad and it erases the 10 good things. I only remember the bad things, those are the only things that stick out in my head. So, I feel like I’m having a bad year defensively.”

Casas has been a key contributor to the MLB-leading 21 double plays his team has turned. And he entered this week’s Mariners series charged with only two errors on the season. Mistakes aren’t always ruled errors, though, and Casas can recite his from memory.

“I know I made a big error in Chicago that was unacceptable, and then there was a pick two days ago that I didn’t make on (Alex) Bregman’s ball,” he said. “Another one that sticks out to me is Trevor (Story’s) throw that I botched on his great play up the middle. So yeah, I got a bunch of errors, and they’ve come in some big situations, unfortunately, and so I feel like I have a lot to work on and a lot to keep improving upon.”

Cora said Casas needs to improve his first step.

“He’s fallen into some bad habits lately, but if we can get that one down, it’ll be better,” Cora said. “He’s making throws, he makes every throw at first base. That’s really good, but yeah, we gotta get him moving at first.”

Asked where he feels he can improve, Casas had a different answer.

“Keep playing the game with a lot of attention to detail, just be anticipative to what I believe is going to happen,” he said. “I know the pitch characteristics that our guys are throwing and I have an idea of how the opposing players are swinging the bat, so I think just trying to think ahead and anticipate the type of ground ball that I’m going to get is going to be important.”

“There’s no ground ball in practice that you can simulate that comes as hard as the ones in the game,” he continued. “When they hit the grass, or whether they hit the dirt, there’s a lot of variables, so really, no two ground balls are the same.”

Casas entered Tuesday hitting .158 with a .466 OPS, and only 12 hits (three doubles, one home run), six walls, and 20 strikeouts in 21 games. His 7.2% walk rate is a far cry from the 14.2% he played to in the first three years of his big-league career. He’s just over a year removed from the freak rib-cartilage injury which kept him sidelined until mid-August. He’s pain-free and confident his bat speed is as it was before the injury.

“I think I’m the same player. Numbers might not reflect that, but physically my swing feels just as strong,” he said.

Consistency is key

The Red Sox optioned reliever Zack Kelly to Triple-A Worcester on Tuesday in order to activate starter Brayan Bello for his season debut.

Kelly entered the season with a 3.95 career ERA over career games between his ‘22 debut and the end of last year. This season, he’s again shown flashes of brilliance but struggled to be consistent. In seven appearances he allowed 10 runs, all earned, on 12 hits. He’s issued two walks, hit two batters, and struck out 11 men in 10 innings.

The right-hander, 30, is one of the hardest-throwers on the staff, with his fastball velocity in the 77th MLB percentile. On the Red Sox, only Garrett Whitlock (79th) and Aroldis Chapman (98th) outrank him. However, though it’s a small sample size, Kelly is also getting hit much harder than in the past: a 46.7% hard-hit rate, compared to 31.7% over the first three years of his big-league career.

“The way that went, it wasn’t the right way,” Cora said of the most recent outing on Sunday. Kelly gave up a single and hit back-to-back batters to load the bases without recording an out, and Justin Wilson allowed all three runners to score.

“I think it’s consistency,” the Sox skipper said. “Like, one good outing in a week, is that good enough? Well, it helps, but we know there’s more there. We do know that. Like, this guy can be a back-end reliever on a championship-caliber team, we just have to get there.”

While Cora praised Kelly for throwing first-pitch strikes, he said the right-hander needed to do so consistently. He also posited that Kelly might be trying to do “too much.”

“To get three outs, we’re trying to use every weapon instead of just being on the attack and get people out,” he said.

With a healthier pitching staff and a high payroll, the margin for error is smaller than in year’s past. Since early in spring training, Cora has stressed the importance of executing. He did so again in discussing Kelly on Tuesday.

“The whole thing about projections and all that, we have to turn the page and we have to execute,” Cora said, “and he knows that.”

Injury updates

Lucas Giolito (mild hamstring strain) will make one more rehab start. The Red Sox expect to activate him from the injured list while in Toronto next week.

Kutter Crawford (right knee) threw off the mound at Fenway Park on Tuesday afternoon, with Connor Wong (hand fracture) catching him. Crawford will fly to Fort Myers, Fla., on Thursday to continue his ramp-up at the organization’s Spring Training complex.