ST. PETERSBURG, Fla. — Colton Cowser heard it for years from his longtime hitting coach Sid Holland, and then outfielder Anthony Santander picked up the refrain early this season. They saw Cowser’s height, his quick hands, his swing speed.

It was a small suggestion, but Holland and Santander felt it could unlock another level from Cowser. Swing a longer, heavier bat, they’d tell the Orioles rookie.

Cowser held out until after the All-Star break. He went into that series against the Texas Rangers with his traditional 33 1/2-inch bat before pulling out a 34-inch bat of the same model. He took a couple of swings in batting practice the day before and then decided, shortly before his first game post-break, to use the 34-inch model.

Santander quickly approved of the decision. “Good,” he told Cowser. “You need to. You’re a big guy.”

And then Cowser became a believer.

In his first at-bat using a 34-inch bat, Cowser swung at Nathan Eovaldi’s hanging curveball on July 19 and powered it 420 feet to right field for a home run.

“OK,” Cowser thought. “I may as well keep using it. That works.”

Perhaps part of this is mental. To find immediate success with a new bat and to stick with it is baseball-esque. Superstition reigns supreme. But there’s at least some level of reasoning to support the switch in bat lengths.

The slightly longer style is still a drop-3 — which means it is 3 inches longer than ounces heavy — but even at 31 ounces there’s just enough added weight to slow Cowser’s bat a tick through the strike zone. He might be a tick behind fastballs at times now, but Cowser’s slightly slower bat improves his chances against off-speed pitches.

And the results are hard to argue with. Since July 19, Cowser is hitting .337 with a .968 on-base-plus-slugging percentage — a sort of surge that rekindles his chances of being named American League Rookie of the Year.

“In this game, it’s better sometimes being a little bit late than early, because, when you’re early, that’s when you start chasing and missing too many balls,” Santander said. “And he listened. And he’s having good results. He’s so talented, and sometimes when we’re in a slump, it’s because something else is going on. I’m so glad for him. He’s got that big bat now.”

The “big bat” is minimally different than Cowser’s old 33 1/2-inch bat, but the weight change is a benefit. It begins at 31 ounces, and the more a bat is used, the heavier the wood becomes. At this point, the bat could weigh around 31.8 ounces, Santander surmised.

Santander made the change to a longer, heavier bat earlier in his career, while he was still a minor leaguer. He jumped all the way to a 35-inch, 33-ounce bat — “Big bat,” he said with emphasis — before evening out to a 34-inch, 31 1/2-ounce bat.

Santander has different bats for different occasions, however. He has three distinct lengths and weights for different matchups or depending on how his body feels that day. He can shift to a 34-inch, 32-ounce bat if he’s overly loose and his swing becomes too quick. Or, on a sore day, he can use a 31-ounce bat.

Whatever the option, though, Santander could clearly see Cowser needed a change. He’d talk to Cowser during batting practice sessions and remind him of the nuances of baseball. Santander recalled his own change, and how it helped him and how it could help Cowser, too.

“That started because I have the same issue before. I can’t swing a 33 1/2 with a 31, because it’s too light and my swing is a little off,” Santander said. “It’s not under control, you know. Getting a heavy bat, it’s going to slow you down a little more, but you’re going to have more control about it. So I see him, his swing is too fast, it’s too quick. I see, [whoosh noise]. And I tell him, like, take a look at [Heston] Kjerstad. Kjerstad has a really fast swing, but he swings a 34, 32. Heavy bat. You’re swinging a lighter bat, so you don’t have the control of that. That’s why you’re sometimes missing the ball this far or you’re too early, because you never are too late.”

There has been a minor but noticeable change to Cowser’s average bat speed since adopting the longer bat. According to Statcast, Cowser’s average bat speed on swings was 74.2 mph from March to June. Since July, Cowser’s average swing speed is 73.4 mph.

So is it the bat? Or is it mental?

A home run in his first plate appearance with a 34-inch bat inspired Cowser to stick with the model after ample urging from Holland and Santander. And the slightly slower bat is a benefit for Cowser as he opens the second half of the season excelling as Baltimore’s leadoff hitter.

Both aspects, from a physical and a mental standpoint, have helped Cowser break out. And that’s all that matters for the Orioles.

“Could be placebo,” co-hitting coach Ryan Fuller said. “But, whatever he’s doing right now, I want him to keep doing.”