Cubs lefty Drew Smyly’s bounce-back lays groundwork for Nico Hoerner’s walk-off single

Cubs left-hander Drew Smyly’s curveball took such a dramatic dive that it hit the ground behind the plate as Mariners star Julio Rodriguez lunged after it and missed for strike three.

‘‘He’s got a funky curveball,’’ catcher Yan Gomes said after the Cubs’ 3-2 walk-off victory in 10 innings Monday against the Mariners. ‘‘He’s made his career out of it.’’

The game ended with heroics from Nico Hoerner, who poked an RBI single into right field for his first career walk-off hit.

It was a bounce-back outing for Smyly, who struck out Rodriguez twice on that curveball and leaned on it to strike out the side in the fifth. He held the Mariners to one run in five innings.

‘‘If you’re trying to decipher a difference between my first game and the second game, I was a little more picky [in the first start],’’ Smyly said, ‘‘not being aggressive and attacking hitters, which is what I like to do. Get ahead in the count.’’

To understand Smyly’s first two starts of the season, it’s necessary to look back at spring training. Smyly’s focus on his arm position this spring was an adjustment the Cubs hoped would pay off during the course of the season.

Sometimes performance dictates a change. But that wasn’t the case when pitching coach Tommy Hottovy noticed Smyly’s arm position had dropped slightly compared to when he was at his best last year.

‘‘If you went only by pitch data, pitch metrics and location, he was doing that,’’ Hottovy said. ‘‘But there was something there that just wasn’t quite where we wanted it.’’

Smyly focused on his arm position when he was planting his foot. And though the process pushed back the switch to ‘‘compete mode’’ that pitchers often make in their last two or so starts of spring training, Hottovy saw Smyly’s arm position trending in the right direction.

‘‘In the end, it’s going to help the pitch shape, it’s going to help location, command, stuff,’’ Hottovy said. ‘‘It’s also going to help recovery, and that was our biggest thing with him.’’

So even though Smyly’s arm position this spring was better than it had been in spring training of 2022, Hottovy pointed out the difference from ‘‘peak Smyly,’’ when he posted a 2.03 ERA from mid-July through the end of August last season.

Hottovy wasn’t worried after Smyly’s first start of this season, in which he allowed six earned runs in 4⅔ innings but mostly limited the Reds to soft contact. Smyly, however, was frustrated.

‘‘It’s tough because in spring you’re able to work on things, but then you can also get into bad habits of focusing too much on one thing or the other,’’ Smyly said. ‘‘And you kind of get sidetracked from the actual game.’’

On Monday, Smyly said his arm position was feeling more natural. And he wasn’t as in his head about his mechanics; he was just attacking.

After establishing his fastball early, he turned to his curve. The pitch accounted for 47% of the pitches he threw and generated seven whiffs, according to Statcast. In the fifth, he threw the curve on 11 consecutive pitches.

He left with a 2-1 lead, which the bullpen maintained until Michael Fulmer gave up a towering solo home run to the Mariners’ Jarred Kelenic in the ninth to send the game into extra innings.

Then it was Horner’s time to shine.

Pinch runner Nick Madrigal, who started on second base because of the extra-innings rule, already had stolen third. Hoerner then went with a slider on the outside corner and sent it the other way.

‘‘I was just so happy,’’ Hoerner said, a sheriff’s hat from Gomes perched on his head to celebrate the occasion. ‘‘What a special thing to experience.’’