ST. LOUIS -- Catcher Yadier Molina was placed on the 10-day injured list ahead of Friday’s opener against the Cubs with a tendon strain in his right thumb. Specifically, it’s a tear in between the thumb and the forefinger.

There is not yet a timetable for Molina’s return or what his treatment will be, although the earliest he could be activated is next Saturday in Chicago. President of baseball operations John Mozeliak said Molina will see a hand specialist on Friday night and that there will be a better idea of treatment and return afterward.

Molina injured the thumb Sunday against the Braves and, after imaging came back negative, tried to play through it while in Philadelphia earlier this week. The problem came with swinging the bat -- not catching or throwing -- so he was out of the lineup the past two games. This is the sixth time Molina has been placed on the injured list over his 16-year Major League career.

Imaging of the thumb Friday morning showed “something more invasive,” manager Mike Shildt said.

“He’s been trying to do what he can the last couple of days, just not something that, after what the imaging looked like today, looked like it wasn’t going to heal with some more time and care,” Shildt said. “For a mortal person, it’d probably be an X amount of time, but for Yadi, it’ll be something different.”

The Cardinals purchased the contract of catcher Andrew Knizner from Triple-A Memphis to take over the backup spot as Matt Wieters, who hit two home runs in the past two days, will stay in the starting spot.

Knizner, a 24-year-old rookie, is the club's No. 2 prospect per MLB Pipeline and has appeared in 37 games for Memphis while batting .286 with five home runs, 17 RBIs and eight doubles.

In 34 plate appearances this season, Wieters is batting .387 with three home runs and nine RBIs.

“What Matt has been able to provide for us when he plays has been impressive,” Mozeliak said. “Now he gets an opportunity to catch every day. Andrew Knizner gets the opportunity to come to the big leagues, and he’ll take the backup role, but we’ll get him some playing time as well.”

The Cardinals signed Wieters to a Minor League deal in February, and he made the team out of Spring Training as Molina’s backup. But starting isn’t unfamiliar to the four-time All-Star and two-time Gold Glove winner.

“I’ve been doing the new role for two months, and I’ve been doing the other role for most of my career,” Wieters said. “[Starting is] something I’m familiar with, and it is a different kind of mindset for preparation each day, but I have some experience doing it.”

Cabrera to stay in rotation

Left-hander Génesis Cabrera will stay in the Cardinals’ rotation and start Tuesday at home against the Reds, Shildt announced Friday.

Cabrera (0-1) was called up from Memphis to make his debut Wednesday in the Cardinals’ 11-4 loss to the Phillies. He lasted 3 2/3 innings, gave up five hits and three earned runs while walking two and striking out five.

But Cabrera’s start was better than it looked on paper, as the left-hander flashed his potential when he struck out the side on just 11 pitches in the second inning and reached 99 mph on the radar gun.

“Overall, [Cabrera’s] stuff looked way different from what all of us experienced in Spring Training, so that was good to see,” Mozeliak said. “He clearly has an electric arm, has a chance to really be an exciting pitcher in the big leagues. His ability to start is exciting.”

Shildt and Mozeliak would not say whether Cabrera will stay in the rotation beyond Tuesday, noting that they’ll take it day by day for the time being.

Alex Reyes moving to Memphis

Alex Reyes’ next start will come for Memphis, likely on Sunday. He pitched 4 1/3 innings in his start for Class A Advanced Palm Beach on Tuesday and gave up seven hits and one earned run while walking one and striking out five.

The right-hander was placed on the 7-day injured list from Memphis after fracturing his left little finger when punching a wall. The trouble now comes from swinging a bat, which he’s still not cleared to do, so there is no timetable for when Reyes might make his return to St. Louis.

“Until we get to that point, which we will slowly work into,” Mozeliak said, “he may have to just stand up there and be a soft out.”