Twins lefthander Caleb Thielbar struggling to hit his rhythm with temperamental fastball

SEATTLE – Caleb Thielbar pitched only twice in the previous 16 days, which was partially by design and a lot by happenstance.

The Twins coaching staff wanted Thielbar to use the first five or so days to work on his fastball, which has the same velocity as last year, but it hasn’t featured as much carry. He entered Saturday with a 7.13 ERA in 25 appearances, yielding 25 hits and 14 earned runs in 17⅔ innings.

“I feel like it’s so much of a timing thing, rhythm with my delivery,” Thielbar said. “I just don’t feel that right now. I’m waiting for it to click because once it does, it usually doesn’t leave. It just hasn’t gotten there. I don’t know why, but I’m trying to figure that out.”

In Thielbar’s last appearance, Thursday against the Arizona Diamondbacks, he threw more curveballs and sliders than fastballs.

“The other day was just better command of the breaking balls,” Thielbar said. “I’ll be able to get by if I can do that, but to be truly back, I need to get the ride on the fastball.”

The frustrating part for Thielbar, the 37-year-old lefthander from Randolph, is his fastball looks the way he wants in bullpen sessions over the last couple of weeks. It just hasn’t translated into games.

It’s a fine line for Thielbar, who was a key contributor to the Twins’ bullpen in the playoffs last year. Righthanded hitters are batting .410 against him this season.

Are there concerns it could be an age-related decline?

“You think about that, but I’m athletic enough. I’m not going to just flat out lose the ability to do this,” said Thielbar, who hasn’t seen any decline with his velocity. “Whether I’m not effective is one thing. ... I realize time isn’t on my side, either. You always think about that stuff. It puts a little more pressure on you, but hopefully you can rise to the occasion and get back to where you need to be.”

Bally Sports North reporter Audra Martin brought a plate of chili-lime-flavored toasted grasshoppers, a concession item at T-Mobile Park, into the clubhouse and asked players if they wanted to eat them for a TV segment.

“No chance,” Jhoan Duran said after he was told what it was in Spanish.

Joe Ryan picked one up, inspected it and flung it across the room toward a trash can. Third base coach Tommy Watkins saw the plate and didn’t stop his stride walking across the room: “No. No.” Carlos Correa declined after he said he just ate, and Max Kepler, who ate one for a similar TV segment in 2017, shook his head no.

Royce Lewis declined after he watched Martin cough while eating it.

“If he hits two home runs today, bring that plate back out,” Lewis said.

• Willi Castro played his 20th game at second base Friday, becoming the second player in MLB history to appear in 20 games at five defensive positions, according to MLB Network. Detroit’s Zach McKinistry accomplished the feat last year. “We’re only halfway through the season, so I wonder what he’s actually going to accomplish by the end of the year,” Twins manager Rocco Baldelli said.