JUPITER, Fla. -- Carlos Martínez had a smile on his face when he walked to the middle of the mound and home plate after he finished throwing Thursday.

His arm felt good after 30 pitches, and the first official bullpen session of Spring Training went well for the right-hander vying for a spot in the rotation.

“I feel great,” Martínez said. “I think I can do more. I feel comfortable.”

Martínez said he threw at around 70 percent to 80 percent Thursday, but he has thrown at full strength since he was cleared for his first bullpen session in the middle of January. On Thursday, Cardinals pitchers were tasked with throwing fastballs down in the zone, aiming for a yellow rope pulled taut in front of every home plate. They achieved that goal if the ball strummed the string on its way into the catcher’s mitt.

“That was my first time for me throwing like that,” Martínez said. “I liked it because it made me focus, stay down. It helped me a lot.”

After spending most of last season as the Cardinals closer, Martínez is eyeing the rotation in 2020. The 28-year-old was a two-time All-Star as a starter in 2015 and ’17, but he’s been plagued by shoulder weakness the past few years. Almost exactly a year ago, on Feb. 19, he was put on a two-week, no-throwing program because of right shoulder weakness. It’s what led to his role in the bullpen last season.

• Spring Training predictions for the Cardinals

This spring, Martínez is healthy. He showed up to camp having lost a few pounds and coming off a strength-focused offseason program. He’ll compete for a rotation spot along with a number of candidates, most notably lefty Kwang-Hyun Kim. Cardinals manager Mike Shildt said Martínez was one of many players who “won the offseason.”

“He’s done a nice job this offseason of competing,” Shildt said. “As far as physically it looks really good. His arm is in good shape. At this time last year, he wasn’t in a good spot from a throwing standpoint. But he’s really done everything he needs to do and to set himself up for success to have that opportunity to compete as a starter.”

How Martínez’s arm recovers from his bullpen session is almost just as important as how he looked and felt during his session. But he said Thursday that he feels strong, comfortable and like he should feel after a bullpen.

That encourages the Cardinals about where Martínez is headed.

“He’s done a good job of the overall health component,” Shildt said. “And then staying ahead of, which is important, some of the things he has a history of. Making sure that the stabilization’s taking place in a lot of areas, including his arm. So he’s in a position to where he can now look to handle what it looks like to be a load of a Major League starter.”

Martínez can’t predict what will happen between now and Opening Day, whether he’ll find himself in the rotation or the bullpen. His focus is on being effective on the mound and being smart off it when taking care of his arm.

But make no mistake -- he thinks of himself as a starter.

“Always,” he said.

Around the horn

• Top prospects Dylan Carlson and Nolan Gorman arrived at camp Thursday. They joined the Cardinals’ starters for fielding drills and batting practice ahead of the first full-squad workout on Monday.

• Along with the coaches, staff, teammates and reporters watching Kwang-Hyun Kim’s first official bullpen with the Cardinals, the Korean left-hander had a few other onlookers Thursday morning. Five players from the SK Wyverns, Kim’s former Korea Baseball Organization team, made the drive from Vero Beach, Fla., to see Kim pitch on their day off from training. Kim was planning on taking them to lunch and to play a round of golf after his workout.