Paul Molitor hates mentioning his own Hall of Fame career in any context regarding his current team. But the Twins manager broke that taboo when discussing Eddie Rosario and his inability to recognize strikes, the habit most responsible for his demotion to Class AAA Rochester on Thursday.

“I walked 19 times as a rookie, and I swung at everything I saw, pretty much,” Molitor said. “Yes. People can improve.”

He’s not asking Rosario to match his own progress; Molitor, after all, retired with a .369 on-base percentage. But “if you’re getting on base 22 percent of the time” — Rosario’s OBP this season is .227 — “you’re not going to be able to steal bases and do other things.”

Molitor said he is confident Rosario was trying to change his approach, though the 24-year-old, who went 1-for-4 with a double and two strikeouts at Rochester on Thursday, said during spring training: “People tell me that I should not change things that worked for me last year. I’m going to try to keep things the same.” But he too often turned promising at-bats into outs by swinging at pitches out of the strike zone, Molitor said.

Rosario was “taken aback” by the news that he was being sent down, Molitor said, despite making repeated mistakes in the field and on the bases. He was mistake-prone last year, too, but 46 extra-base hits in 122 games buys a lot of patience. This year?

“All you have to do is look at the stat line. It’s not very good,” GM Terry Ryan said of the outfielder’s .209 average and eight extra-base hits. “We gave him every opportunity to get going, and it just didn’t work.”

Work is what it will take to get back, Molitor said, and he included a warning. “He’s going to have to get to work fast. We have [Byron] Buxton and [Max] Kepler and [Adam Brett] Walker” waiting for their opportunity in the major leagues, too,” he said. “We’ll see how he responds.”

Meet the new guy

On Monday, Robbie Grossman exercised the termination provision of his contract with Cleveland and was granted free agency. On Tuesday, he agreed to a contract with the Twins. On Wednesday, he was in a Rochester uniform at Charlotte, though he didn’t play. On Thursday, he was in a Twins uniform at Target Field.

“They told me to be ready,” said Grossman, 26. “It’s not my first year in this business. I’m excited for this opportunity.”

Molitor isn’t sure what the opportunity is yet. But Grossman gives him a switch-hitting bat and another option in the outfield. “He’s not a burner, but intelligent in terms of how he runs bases and makes decisions. Capable of playing all three outfield positions,” Molitor said.

Grossman, who was assigned Joe Nathan’s old No. 36, is a career .240 hitter in 190 games, all with the Astros, but he was released by Houston last winter after batting .143.

Gibson to Fort Myers

Kyle Gibson threw three simulated innings of 15 pitches apiece Thursday, declared his sore shoulder healthy again, and prepared to head to Florida. He will start for Class A Fort Myers on Sunday, then again Friday with Ryan in attendance. The Twins will decide at that point whether to activate him.

“I need to be ready to throw 90-100 pitches,” Gibson said. “If it takes three starts to build up, it takes three.”

Gibson said he still feels an odd, though waning, pain in his shoulder when he extends himself to throw long toss, from 120 feet or so. But on the mound, the pain is nonexistent, so he’s convinced it won’t be a factor again. He still isn’t certain when or how he injured the shoulder — it was on a glove-side pitch to Bryce Harper or Ryan Zimmerman at Washington, and didn’t become serious until the next day.

Shortstop Eduardo Escobar starts his own rehab, from a groin injury, for Fort Myers on Friday.