Walker (4-8) conceded four runs on eight hits and two walks over six innings to take the loss Sunday at Miami. He struck out one.

The Philadelphia right-hander coughed up all four runs in the opening frame, highlighted by a 424-foot, three-run long ball from Otto Lopez. Walker did not fool the Marlins lineup, generating just four whiffs out of his 87 total pitches, and he's now winless over his last six starts. Over that span, the 33-year-old has produced an unsightly 5.23 ERA, 1.56 WHIP and 16:11 K:BB in 32.2 frames, morphing back into a pitcher best left for the waiver wire. Walker currently lines up to make his next start at home against Kansas City next weekend.

Red Sox manager Alex Cora said that Tolle won't start Wednesday's game against the Athletics in Sacramento but could still factor into the team's pitching plan that day, Ian Browne of MLB.com reports.

Because Tolle has typically been pitching on at least five days' rest this season and is coming off a poor showing Friday against the Diamondbacks in which he surrendered five earned runs over three innings, the rookie won't be asked to handle a traditional starting role when his turn in the rotation comes up Wednesday. The Red Sox could still use Tolle as a multi-inning reliever behind an opener Wednesday, but the 22-year-old lefty was still likely have his pitch count monitored carefully in that scenario.

Castillo (9-8) earned the win over Atlanta on Sunday, allowing one run on four hits and no walks across six innings. He struck out six.

It was a much-needed outing for Castillo, who earned his first win since July 28 -- he'd struggled to a 10.06 ERA in his previous four starts (17 innings). Overall, Castillo's ERA sits at 3.85 on the year with a 1.27 WHIP and 144:44 K:BB through 29 starts (161.1 innings). Castillo will look to build on Saturday's effort his next time out, currently lined up for next week against the Angels.

Rasmussen allowed three hits and three walks across five scoreless innings in a no-decision Sunday against the Guardians. He struck out two.

While the Rays ultimately came up short Sunday, it was an encouraging effort from Rasmussen after he allowed three home runs to the Mariners in his last outing. The 30-year-old Rasmussen's ERA is down to 2.64 on the year with a 0.98 WHIP and 117 strikeouts through 28 starts (139.2 innings). He's currently scheduled to face the Cubs on the road his next time out.

Messick (2-0) earned the win Sunday over the Rays, allowing one run on eight hits across six innings. He struck out four.

Messick allowed at least one hit in every inning, though he was able to navigate through traffic, holding Tampa to a Carson Williams solo homer. Overall, it was an encouraging outing from Messick after he gave up three runs on nine hits in just 3.2 innings his last time out against the Red Sox. The rookie left-hander sports a 1.93 ERA with a 1.33 WHIP and 18:3 K:BB through his first four major-league starts (23.1 innings). Messick's currently lined up to face the White Sox at home in his next outing.

Sugano was removed from Sunday's start against the Dodgers due to right foot discomfort, Roch Kubatko of MASNSports.com reports.

The right-hander surrendered four earned runs on seven hits -- including three home runs -- across his first three innings before being struck by a comebacker in the fourth inning, which ended his day. Sugano limped off the field after the incident and should be considered day-to-day as he continues to be evaluated.

Mazur is expected to work as a bulk reliever behind opening pitcher Tyler Phillips during Sunday's game against the Phillies, Daniel Alvarez-Montes of ElExtraBase.com reports.

Mazur had made a pair of starts for the Marlins upon being recalled from Triple-A Jacksonville on Aug. 28, but Miami appears set to use the right-hander behind an opener with the hope of generating better results from him. Over his three total starts with Miami this season, Mazur has gone 0-2 with a 5.74 ERA, 1.53 WHIP and 12:5 K:BB in 15.2 innings.

The Mets selected Sproat's contract from Triple-A Syracuse ahead of his scheduled start Sunday in Cincinnati.

Sproat becomes the Mets' third major prospect to join the rotation after Jonah Tong and Nolan McLean both received call-ups in recent weeks. The 24-year-old Sproat isn't guaranteed any starts beyond Sunday, but with Kodai Senga now at Triple-A, the Mets have room for the right-hander if they elect to maintain a six-man rotation heading into the upcoming week.

Strider isn't starting Sunday's game against the Mariners and will instead take the mound Tuesday against the Cubs, Mark Bowman of MLB.com reports.

Atlanta indicated that the decision isn't injury-related, so the organization is seemingly just looking to get Strider some extra rest during the final stretch of the season. It's been an underwhelming campaign for the right-hander, who missed a month early in the season due to a hamstring injury and has a 4.97 ERA, 1.39 WHIP and 106:41 K:BB across 101.1 innings. Joey Wentz is moving up in the rotation to start Sunday's series finale versus Seattle.

Alvarez is scheduled to start Sunday's game against the Cubs at Wrigley Field.

As anticipated, Alvarez will stick around in the Washington rotation after delivering a sterling performance in his MLB debut this past Monday against the Marlins. The 26-year-old lefty had a no-hitter going through the first four innings and ultimately allowed just three baserunners while striking out four batters across five frames, earning the win and helping the Nationals halt an eight-game losing streak. Alvarez will get a stiffer test for his second MLB start as he matches up against a Cubs offense that ranks fifth in baseball with a 109 wRC+ on the season, though Chicago could be without two of its key batters in Kyle Tucker (calf) and Pete Crow-Armstrong (knee).