Diamondbacks manager Torey Lovullo announced Sunday that Jameson is moving into the starting rotation while Zach Davies (oblique) is on the injured list, Theo Mackie of The Arizona Republic reports.

EDGE Analysis

Jameson has been effective out of the bullpen for the Diamondbacks thus far with a 2.16 ERA and 8:5 K:BB over 8.1 innings in three appearances. The right-hander has worked at least two innings in each of his outings -- including four against the Dodgers on March 31 -- and he should be stretched out after competing for the fifth starter spot in the Cactus League. If Jameson pitches well over his first few outings he has a good chance to stay in the rotation even after Davies is ready to return. If the 25-year-old were to struggle, the Diamondbacks could turn to top prospect Brandon Pfaadt in the coming weeks.

Jameson (2-0) allowed one walk while striking out one over 2.1 scoreless relief innings to pick up the win in Friday's 6-3 victory over the Dodgers.

EDGE Analysis

Jameson, who lost out on the fifth starter job in spring training, has thrived as a reliever. In three appearances, the right-hander earned two wins and a save while never pitching fewer than two innings. Arizona manager Torey Lovullo appears to have made a shrewd decision in moving him to the 'pen in a multi-inning role instead of having him start in the minors. The dark lining to this silver cloud are the two home runs and five walks allowed along with an unsustainable .158 BABIP, which project a 6.23 FIP. Fortunately for Jameson and the D-backs, both homers were solo shots and the free passes have not hurt.

Jameson picked up the save Tuesday against San Diego. He allowed one run on three hits and one walk while striking out two over two innings.

EDGE Analysis

He lost the battle for the final rotation spot to Ryne Nelson, but Jameson is having a great opening week regardless as he grabbed his first win of 2023 on Friday and now has his first career save to go with it. The back end of the Arizona bullpen has been shaky early on and Jameson, a top 10 prospect in the organization, could quickly emerge as a go-to option in high leverage. He could also stretch back out into a starter's role at some point.

Jameson (1-0) picked up the win in Friday's 2-1 victory over the Dodgers, allowing one run on two hits and three walks over four innings of relief. He struck out five.

EDGE Analysis

Merrill Kelly got the start but lasted only 3.2 innings and 74 pitches, forcing the Diamondbacks to turn to their bullpen early. Jameson stepped up with an impressive performance in long relief, firing 38 of his 66 pitches for strikes with 13 swinging strikes. The 25-year-old will continue in his bullpen role for now, but if a spot opens up in the rotation, expect him to get first crack at filling it.

Jameson will begin the 2023 campaign working out of the bullpen after Ryne Nelson was named Arizona's No. 5 starter Sunday, Nick Piecoro of The Arizona Republic reports.

EDGE Analysis

Neither pitcher performed particularly well during spring training with ERAs above 7.00, but it'll be Nelson that receives the first crack at the rotation in 2023. Jameson was lights out in his first taste of the majors last year with a 1.48 ERA and 24:7 K:BB across 24.1 innings (four starts).

Jameson allowed four runs on four hits and four walks while striking out seven over 4.1 innings in Thursday's split-squad start against the Dodgers.

EDGE Analysis

Jameson gave up three runs in the first inning, then got a ton of run support -- 10, in fact -- during the bottom half of the inning. He settled in after that, although he dealt with base runners in four of the five innings he worked. Jameson's competition for the No. 5 starter job, Ryne Nelson, pitched in the other split-squad game and allowed three runs on four hits and two walks over 4.2 innings against the Cubs. Neither pitcher has a statistical advantage in the job battle, which looks like it will go down to the wire.

Jameson threw in a minor-league game Friday, Nick Piecoro of the Arizona Republic reports.

EDGE Analysis

Jameson was one of several pitchers affected by the two-game rainout Wednesday and was adjusted to throw Friday. Arizona manager Torey Lovullo said Jameson showed excellent velocity on his fastball, which touched triple digits. The manager also said nothing should be read into the fact that he didn't pitch in a Cactus League game. Jameson is one of four starters still competing for the final spot in the rotation.

Jameson allowed five runs on seven hits and one walk while striking out four over three-plus innings in Sunday's spring start against the Rockies.

EDGE Analysis

Jameson allowed a pair of home runs in his fourth Cactus League start. The right-hander got off to a good start this spring in his quest to claim the No. 5 starter job, but he's been knocked around his last two times out with eight runs and 11 hits allowed over the last 5.2 innings. Jameson's main competition for the job, Ryne Nelson, appeared as a reliever Sunday and fared better (one run, four hits, 2.2 IP).

Jameson pitched better during his start Monday after going to his changeup, Steve Stockmar of MLB.com reports. "Early on in games, I don't want to use it if I don't have to," he said. "I probably should have gone to it a lot earlier than I did."

EDGE Analysis

Jameson was worked by the Royals in the first couple of innings Monday, before manager Torey Lovullo removed him from the game with two outs in second frame. The manager brought Jameson back in for the third inning, and the right-hander was dialed in with the help of his changeup. The manager believes he was sharp but made mistakes on 0-2 pitches that hurt. Jameson pitched well in his first two Cactus League starts and is considered the frontrunner for the final rotation spot.

Jameson allowed three runs on four hits and one walk while striking out give over 2.2 innings in Monday's spring start against the Royals.

EDGE Analysis

Jameson gave up a first-inning home run then allowed several base runners in the second before being pulled. He came back out for the third inning to face one more batter in what was his first clunker in three Cactus League starts. Of the group battling for the final rotation spot, Jameson has been the best among Tommy Henry and Ryne Nelson.