PHOENIX -- The Mets' rotation shuffle, which they announced Wednesday night after landing in Arizona, was due to a blister that tore off of Steven Matz's left middle finger earlier this week. After team athletic trainers treated the blister, they recommended the Mets push Matz's start back from Thursday to Saturday -- a "luxury," as Matz called it, that the team could afford after skipping Jason Vargas' last turn through the rotation.
A relatively fresh Vargas started Thursday in Matz's place, and the team is confident Matz will be at full strength Saturday. The left-hander threw a light side session at Chase Field without issue.
The Mets had reason to be cautious with Matz, who has improved markedly in recent weeks. Since May 5, Matz owns a 2.68 ERA in seven starts.
Injury updates
Outfielder Jay Bruce will likely receive multiple days off due to lower back soreness that has radiated into his hip and buttocks. Bruce was unavailable to pinch-hit Thursday, according to manager Mickey Callaway, and is unlikely to be in the starting lineup Friday.

The break comes at a notable time for Bruce, who has gone 109 consecutive plate appearances without a home run, and is batting just .216 with a .624 OPS. Bruce has also committed multiple defensive gaffes in recent days, including a misplay during Wednesday's 2-0 loss to the Braves.
"I think he'll get a breather, mentally," Callaway said. "What we're trying to do is get him healthy so he can go out there and do his job."
Callaway also called infielder Wilmer Flores' return from the disabled list "imminent," indicating he will meet the team this weekend in Arizona. Sidelined since May 28 with a sore back, Flores homered Thursday in his third rehab game for Class A Advanced St. Lucie, and has collected six hits over those three games.
When Flores returns, the Mets must decide whether to option utility infielder Luis Guillorme back to Triple-A Las Vegas, or perhaps cut ties with struggling veteran Jose Reyes.
Movin' on up
The Mets made two notable Minor League promotions Thursday, bumping first baseman Peter Alonso and infielder Jeff McNeil from Double-A Binghamton to Las Vegas. McNeil and Alonso ranked second and third in the Eastern League in OPS, respectively, trailing only Vladimir Guerrero Jr.
The Mets' fourth-ranked prospect, according to MLB Pipeline, Alonso hit .314 with 15 home runs over 65 games with Binghamton, and profiles as an offensive-minded right-handed first baseman. He takes the Las Vegas roster spot of Dominic Smith, whom the Mets recently promoted to the Majors.
McNeil, 26, is enjoying a breakout season in his sixth Minor League campaign, batting .327 with 14 homers in 56 games at Binghamton. He could join the Mets' bench at some point this season.
Bullpen patch
A new face met the Mets Thursday in Arizona, where right-handed reliever Chris Beck joined the bullpen. The Mets claimed Beck, 27, off waivers from the White Sox, after he posted a 4.18 ERA in 14 appearances.
"Really good arm, got really good stuff, from what I remember," said Callaway, who, as Cleveland's pitching coach, faced Beck throughout his White Sox career the past three seasons. "Not scared to challenge guys. So we're excited to have him in the organization, and see what he can do."
To make room for Beck, the Mets optioned right-hander Tim Peterson to Las Vegas.
"It's one of those situations where you kind of just hope somebody does take a flyer on you," Beck said. "They're really not sure what they're getting into. Luckily, I've interacted with Mickey before in Cleveland. I've seen him the past couple of years. So it's kind of refreshing -- a new start. I'm excited about it. There's a lot of history here with the Mets. I'm really just here to get the ball rolling."
Draft signings
The Mets announced a spate of six more Draft signings, including eighth-round pitcher Tylor Megill. The team has signed 18 of its 40 Draft picks -- though the top six picks, including first-round outfielder Jarred Kelenic, remain unsigned.