The Padres shut Nix down Thursday after he experienced right arm soreness following his exhibition appearance Tuesday versus the Athletics, AJ Cassavell of MLB.com reports.

EDGE Analysis

Nix started the Cactus League game and tossed one inning before the contest was cancelled due to rain, then threw three more simulated frames in the batting cage. His arm was still bothering him two days later, prompting the Padres to shelve him temporarily and send Nix in for tests, which revealed no structural damage. The Padres are hopeful that Nix will only need a few days of rest before resuming his throwing program next week, but his shaky health could damage his chances of winning the final spot in the Opening Day rotation. Robbie Erlin and Bryan Mitchell along with prospects Chris Paddack, Logan Allen and Cal Quantrill are among the other names competing for the final rotation opening.

Nix has been working on his slider, Dennis Lin of The Athletic reports.

EDGE Analysis

Along with his improved slider, Nix believes improved health -- he underwent sports hernia surgery in the offseason -- will lead to a more consistent sophomore season. The right-hander relied primarily on a fastball, curveball and changeup in his rookie season; he went 2-5 with a 7.02 ERA and 21:13 K:BB across nine starts (42.1 innings). Nix, who is competing for a rotation spot in camp, has allowed one run with a 3:3 K:BB through two spring appearances (4.2 innings).

Nix (2-5) allowed four earned runs on five hits and three walks while striking out none across four innings to take the loss Saturday against the Diamondbacks.

EDGE Analysis

The big blow against Nix came in the fourth inning when he allowed a three-run home run to Ildemaro Vargas. He pitched fairly effectively otherwise, generating eight groundball outs and allowing only one other extra-base hit. However, the 22-year-old failed to show that he could pitch effectively at the major-league level, posting a 7.02 ERA and 1.54 WHIP across 42.1 innings.

Nix threw four innings Sunday, giving up six runs on seven hits and two walks in the 7-6 win over Cincinnati. He struck out five and allowed a home run in the no-decision.

EDGE Analysis

Nix has been rocked for 11 runs in 10 innings over his last two starts, launching his ERA up to 6.00 this season. He had allowed just one run through four innings before giving up a two-run double and three-run homer without recording an out to start the fifth. Nix will take on the Rangers next Sunday if he gets another shot in the rotation.

Nix (2-3) pitched six innings and took the loss Sunday, yielding five runs on five hits and two walks while striking out four in the 7-3 loss to Colorado.

EDGE Analysis

Nix had allowed just three runs through six innings, but allowed two baserunners before being lifted in the seventh. Trey Wingenter then gave up both those runs on a Chris Iannetta double. It was a disappointing outing for the rookie right-hander after he allowed just one run in 8.1 innings during his last start. Nix will carry a 4.85 ERA into Cincinnati on Saturday.

Nix (2-2) got the win Tuesday, allowing just one run on eight hits over 8.1 innings against the Mariners. He did not record a strikeout or a walk.

EDGE Analysis

It was a terrific, yet strange outing for the rookie -- his first one without either a walk or a strikeout -- as he recorded just one swinging strike and needed only 79 pitches (59 strikes) to get through 8.1 innings as a result. Nix entered the ninth inning in line for a complete-game shutout, but after yielding a one-out solo homer to Nelson Cruz, manager Andy Green turned to Kirby Yates to lock down the 2-1 win. The 22-year-old will take a 4.05 ERA and just 7:5 K:BB across 20 innings into Sunday's start against the Rockies.

Nix (1-2) got the loss Wednesday, allowing three runs on five hits and a walk while striking out two over five innings against the Rockies.

EDGE Analysis

It was a much better outing than his last time out, when he got tagged for five runs against Arizona and didn't make it out of the first inning, but it was still the 22-year-old's second loss in as many tries. He sports an unsightly 6.17 ERA in 11.2 major-league innings, but the numbers were much better this year in the minors to the tune of a 1.84 ERA in 10 starts across both Double-A and Triple-A. He'll look to get back on track Tuesday against Seattle.

Nix (1-1) failed to escape the first inning Thursday, serving up five runs on five hits with two walks and a strikeout while taking the loss against the Diamondbacks.

EDGE Analysis

Nix was hit hard right from the get-go, allowing the Diamondbacks to bat around in the first inning before exiting with the bases loaded. This outing was a stark contrast from the rookie's first start, when he fired six scoreless frames against the Phillies. The 22-year-old earned his recent promotion after posting a 1.86 ERA and 4.9 K/BB ratio over 58.2 innings across two levels in the minors. Manager Andy Green commented on the rough outing, stating that he can "get an indication of how these guys are wired and how they respond to adversity," which is good sign that the rookie will get a shot to redeem himself. Nix will get a chance to do just that in a tough matchup at Coors Field against the Rockies next Wednesday.

Nix will pick up another start Thursday against the Diamondbacks.

EDGE Analysis

While there wasn't a direct path to the rotation open for Nix after he was recalled from Triple-A El Paso last week, there was never much doubt he would receive a second start after dazzling in his MLB debut Aug. 10. Nix shut out the playoff-contending Phillies for six innings, conceding only four hits and two walks to pick up the win. The 22-year-old should get a chance to showcase his stuff over the final month and a half of the season as he looks to stake his claim to a full-time role with the big club in 2019.

Nix was called up from Triple-A El Paso prior to his start against Philadelphia on Friday.

EDGE Analysis

As expected, Nix was officially called up Friday as he gears up for his first start at the big-league level. In a corresponding move, Phil Hughes was designated for assignment.