Walker will draw the start for the Phillies' series opener against the Mets on Thursday, Todd Zolecki of MLB.com reports.

Walker was relegated to the bullpen following his last start against the Astros on Aug. 28, when he allowed six runs on 13 hits and one walk over six innings. He allowed five runs (four earned) across his first two relief outings, but after Walker tossed three scoreless innings against the Mets on Saturday, manager Rob Thompson has decided to give the 32-year-old right-hander another look as the club's No. 5 starter. Overall, Walker holds a 6.29 ERA, 1.63 WHIP and 55:31 K:BB across 78.2 innings this season.

Williams (elbow) is on track to return from the 60-day injured list this weekend versus the Cubs, Mark Zuckerman of MASNSports.com reports.

Williams allowed two runs over 7.1 innings in two rehab starts with Double-A Harrisburg, throwing 73 pitches in his most recent outing Sunday. He should be lined up to start Friday in Chicago, although the exact date for his return hasn't been revealed yet. Williams has been sidelined since late May with a right flexor strain. He had collected a 2.22 ERA, 1.08 WHIP and 47:16 K:BB through 56.2 innings before getting injured.

The Rockies activated Senzatela (elbow) from the 60-day injured list ahead of his scheduled start Monday versus the Diamondbacks at Coors Field.

Senzatela has completed the long road back from Tommy John surgery, which he underwent last July. The veteran right-hander maxed out at four innings and 68 pitches over his five rehab starts prior to being activated, and the Rockies are likely to keep a close eye on his workload in the final two weeks of the season.

Giants manager Bob Melvin said Wednesday that Harrison (shoulder) is unlikely to be activated from the 15-day injured list before the season ends Sept. 29, MLB.com reports.

Though the left shoulder inflammation that sent Harrison to the IL on Sept. 6 has been deemed mild following an MRI, the young southpaw won't be asked to ramp back up with little time left in the season. Harrison had already logged a career-high 124.1 innings prior to being deactivated, which is likely a factor in the organization's decision to shut him down. Over his 24 starts this season, Harrison went 7-7 with a 4.56 ERA, 1.34 WHIP and 118:42 K:BB.

Ray (hamstring) threw another bullpen session Saturday and remains hopeful to return from the 15-day injured list to make one start before the end of the season, MLB.com reports.

Ray faced live hitters in batting practice this past Wednesday, but the session was cut short after 42 pitches when he began experiencing fatigue. The southpaw appears to have avoided a major setback, however, given that he was back on the mound just a few days later. Ray will likely still need to face live hitters on at least one more occasion before the Giants feel comfortable bringing him back from the IL, and he could be on a limited pitch count if he reaches his goal of making one more start for the big club. Landen Roupp should make at least one more turn through the rotation as the Giants' fifth starter until Ray is ready for activation.

Montgomery is slated to start Tuesday's game against the Rockies at Coors Field, Jesse Friedman of GoPHNX.com reports.

As expected, Montgomery will return to the Arizona rotation as a replacement for the injured Ryne Nelson (shoulder) following a three-week stint in the bullpen. Montgomery shifted to a relief role after producing a 6.44 ERA over his 19 starts this season, and he didn't fare much better over his four appearances out of the bullpen (4.85 ERA, 1.38 WHIP and 6:4 K:BB in 13 innings). The southpaw covered three-plus innings in three of those relief outings, so he at least should be relatively stretched out as he re-enters the rotation Tuesday.

Oviedo (elbow) has been throwing from 120 feet four times per week, MLB.com reports.

Oviedo has progressively ramped up his throwing distance and has not experienced any documented setbacks. He is expected to be ready for spring training, though his role on the team is unclear given the number of options the Pirates are projected to have for the rotation.

Mikolas allowed two runs on three hits over five innings in a no-decision Sunday. He struck out four during the loss to Toronto.

Mikolas worked through four shutout innings before coughing up a two-run shot to Davis Schneider in the fifth. Mikolas has failed to complete six innings in four straight starts, posting a brutal 8.10 ERA during that stretch. He hasn't earned a win since July 21 and owns a 6.80 ERA in nine outings since then. Mikolas will carry a 5.49 ERA into his next matchup, which is projected to be at home against the Guardians.

Gallen did not factor into the decision in Sunday's win over the Brewers, allowing three runs on six hits and two walks while striking out seven over five innings.

Gallen was able to work around some traffic on the bases in both the first and third innings to keep the Brewers off the scoreboard but didn't have the same fortune in the fifth. Eric Haase and Brice Turang started off the frame with singles before Jackson Chourio brought them all home with a home run to left center. It was just the second home run Gallen has given up since July 20 and he's struck out at least seven in five straight starts, however he's also issued multiple walks in 10 of his last 11 starts. For the year, he's at a 3.61 ERA, 1.28 WHIP and 140:51 K:BB in 137 innings and lines up for another meeting against the Brewers in Milwaukee this weekend.

Hall did not factor into the decision during Sunday's loss to the Diamondbacks, allowing five runs on five hits and three walks while striking out four in three innings.

Four singles in the first inning led to two runs for the Diamondbacks. They would score three more in the third with just one hit after Hall loaded the bases and Pavin Smith cleared them with a double. It was a step backwards for Hall, who was working on 12.2 scoreless innings across his last three appearances coming into Sunday. He's shown upside at times but owns a 4.91 ERA, 1.64 WHIP and 38:20 K:BB in 36.2 innings. It's possible he gets another start, but he'll likely return to a relief role for now.