When pitcher Julio Teheran was called upon to start for the Braves in the past two seasons, it was strictly as a fill-in. He felt pressure to make a good impression each time, but lacked the confidence and pitch repertoire to excel against big-league hitters.

Things have changed significantly for Teheran, who’s now a member of the starting rotation and makes his season debut Saturday against the Chicago Cubs.

“I can’t wait to get out there,” he said Friday, seated at his locker next to shortstop Andrelton Simmons. “It’s way different than before. That’s where I want to be. That’s what I’m ready to do.

“I feel relaxed now. I have the confidence.”

And the Braves have confidence in Teheran, 22, who has been their top-rated pitching prospect for three years in a row. He looks ready to shed the prospect label and become a major league pitcher.

He enters the season with a new approach from when he was 7-9 with a 5.08 ERA in his second season at Triple-A Gwinnett, which doubled his ERA from 2011. During winter ball in the Dominican Republic, he worked on his slider and developed a sinker at the Braves’ recommendation.

Instead of attempting to throw 94-95 mph straight fastballs by hitters, as he often did in the minors and in his limited major-league starts, Teheran began to change speeds and mix his pitches. With encouraging results. In his final three winter-ball starts, he allowed only two hits in 16 2/3 scoreless innings, with 15 strikeouts and four walks.

He rode that momentum into spring training, where he was 3-1 with a team-best 1.06 ERA in six Grapefruit League starts, with an attention-grabbing 35 strikeouts and nine walks in 26 innings.

Veteran catcher Gerald Laird, who signed with the Braves as a free agent, hadn’t seen Teheran pitch before he caught him this spring.

“The biggest thing, from what I heard about him in the past, was how (much more) he pounded the zone,” Laird said. “He threw strikes, pitched to contact, established his fastball, showed confidence in that two-seamer. And every time I called off-speed pitches, he was able to fire those in for strikes, too.

“So he’s throwing multiple pitches for strikes. I think every outing he just gained more confidence with everything.”

Laird caught Teheran several times in spring training, and manager Fredi Gonzalez liked how the two worked together. Gonzalez plans to mix and match catchers Laird and Evan Gattis with the other four starters until Brian McCann returns from the disabled list, but Gonzalez will have Laird catch Teheran.

“I think it only makes sense, you have a veteran guy catching a rookie,” Gonzalez said. “Not have two rookies, Gattis and Teheran, hook up together. That’s not a good idea. From what I saw, I thought (Laird) did a nice job handling him.”

That’s fine by Teheran.

“We had good communication in spring training,” he said of working with Laird. “I tried to not shake him off, tried to throw whatever he called for. Most of the time we had the same idea what we were going to do, and it worked.”

Teheran is 1-1 with a 4.91 ERA in four major league starts, two in each of the past two seasons. But he’s never been a member of the rotation until now and never felt so armed to get out hitters as he does now.

Gonzalez looks at him differently, like just another member of the rotation.

“I treat him like any other guy, where before you almost had the kid gloves on with him,” Gonzalez said. “You didn’t want to have something go bad and have him take a step back. But right now — you still take care of him because he’s a young pitcher. But as far as the other stuff, let him learn, let him get through some adversity, get into some jams, and let him pitch.”

B.J.'s slow start: While his brother Justin Upton was off to a blazing start — his first-inning homer Friday was his third in four games for the Braves — B.J. Upton was struggling.

The center fielder was 0-for-11 with seven strikeouts in three games before Friday, when he popped out on a 3-0 pitch to end the first inning. The 3-0 count was notable only because didn’t draw a walk during spring training and had none in the first three games.

He and Gonzalez weren’t concerned about the slow start.

“I hit the ball pretty well all spring training,” said B.J., who hit .347 (26-for-75) in Grapefruit League play, with six doubles, two homers and 14 strikeouts. “It’s just one of those rough spots right now, man. But it’s nothing to get stressed about. That’s why you get 700 plate appearances. Just keep working, it’ll happen.”

Gonzalez said: “B.J.’s going to hit. Everybody goes through these periods at any given time during the season, it just so happens that he’s doing it the first three games, so it gets magnified.”