ST. LOUIS – After Dallas Keuchel exercised the opt-out clause in his minor league contract, the Twins had to decide Thursday whether to add him to their major league roster or allow him to enter free agency.

The Twins chose to call him up and insert the 2015 American League Cy Young winner into their starting rotation. Keuchel, 35, was promoted from Class AAA St. Paul and struggling starter Joe Ryan was placed on the 15-day injured list with a left groin strain.

Keuchel, a lefty, was named the International League pitcher of the month for July. In six minor league starts after a disastrous 2022 season, he posted a 1-0 record and a 1.13 ERA with 28 strikeouts and 12 walks in 32 innings. He will meet his new teammates Friday and he's expected to make his Twins debut Saturday or Sunday against the Diamondbacks.

"He's had a ton of success at the major league level, and he's spent a lot of his own time and energy devoted to getting back to where he wants to be," Twins manager Rocco Baldelli said. "He's a very motivated guy right now."

Keuchel exercised his opt-out clause after the trade deadline passed Tuesday, which gave the Twins 48 hours to add him to their 26-man active roster or release him. José De León, who is out for the season, was transferred to the 60-day injured list to make room for Keuchel on the 40-man roster.

There are questions about how Keuchel's pitch mix will translate to major league hitters, which is why he didn't draw more trade interest. In his last start with the St. Paul Saints, Keuchel's fastball topped out at 88 mph. He went 2-9 with a 9.20 ERA in 14 starts with the White Sox, D-Backs and Rangers last year.

After contemplating retirement, Keuchel trained at Driveline, a data-driven baseball facility, in Arizona. He had an 81-55 record and a 3.25 ERA in 175 starts from 2014-20. In the past two years, he owns an 11-18 record with a 6.35 ERA in 44 starts.

"However this plays out with the Twins, we've loved every minute in Minnesota," Keuchel's wife, Kelly Nash, wrote on Twitter on Wednesday. "[Twins president of baseball operations] Derek Falvey believed in Dallas and gave him an unbelievable opportunity to get back in the game that he loves. Grateful is the biggest understatement of our year."

Buxton sits again

Byron Buxton, who was scratched from Wednesday's lineup, was out of the lineup again Thursday because of right hamstring tightness.

"If he's not feeling significantly better by [Friday], we probably have to look into getting it looked at and having the doctor take another look at it," Baldelli said.

Etc.

• Brooks Lee, the Twins' 2022 first-round pick, was promoted to Class AAA on Thursday. The switch-hitting shortstop hit .292 in 87 games at Class AA Wichita with 11 homers and 61 RBI. He led the Texas League with 31 doubles, was sixth with 102 hits and eighth with 63 runs scored.

• The Twins had assistant bench coach Tony Diaz serve as their first-base coach Wednesday because Hank Conger was ill.