PEORIA, Ariz. -- The Padres' bullpen is one of the sport's deepest. But that depth took a hit Monday.
Miguel Diaz will require arthroscopic surgery to repair a torn meniscus in his right knee Wednesday. The right-hander will be sidelined at least six to eight weeks, and he's expected to miss the start of the regular season.
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Diaz, who posted a 4.82 ERA in 11 appearances last season, sustained the injury halfway through his Saturday bullpen session. As he loaded to throw, Diaz winced in pain, and the Padres' staff called for athletic trainers before he walked off under his own power.
"He was a guy coming in, competing for a spot in the bullpen," said Padres manager Andy Green. "He was a guy when he was up with us last year, he punched a lot of people out. He has four real weapons."
Diaz struck out 30 hitters in his 18 2/3 innings -- including four in his first big league inning of the season against Arizona last July.
A Rule 5 selection in December 2016, Diaz made significant improvement last year, and the 24-year-old would've factored into the competition for the role of long man. As things stand, there are probably at least two places available in the Padres' bullpen.
"His stuff's good," Green said. "He's got a real possibility of impacting our big league club in a positive way this year. ... It's disappointing for him personally and for all of us that we're going to have to wait a little bit longer. But we've seen some strides."
Full squad reports
All 70 roster hopefuls were in camp Monday, when the full Padres squad was required to report to the Peoria Sports Complex. But two players who aren't on the roster remained the focal point.
The Padres have continued to display interest in star free agents Manny Machado and Bryce Harper, and the current group has taken note.
"It shows where this organization's at in the process right now," said first baseman Eric Hosmer. "We're trying to win baseball games, and those are the two guys on the market that can probably help you do that better than anybody else out there."
Said second baseman Ian Kinsler: "It's exciting. Hopefully that happens. But if it doesn't, I don't think anybody's going to blink an eye. Everybody's going to continue to work hard, prepare for the season."
Position change for Kinsler?
The Padres envision something of a utility role for Kinsler this year, as the veteran presence in a young infield. Kinsler, meanwhile, hasn't begun envisioning any specific role for himself. He's adaptable.
"You play that by ear," Kinsler said. "You see what the team needs, what the situations are and how you can help the team."

Kinsler is almost certainly going to get reps at third base this spring. He's projected to open the season at second, with Luis Urías at short. But when top shortstop prospect Fernando Tatis Jr. arrives, that could push Urias back to second and Kinsler to third.
Kinsler, the reigning American League Gold Glove Award winner at second base, doesn't think the transition to third base would be so difficult -- despite the fact that he last played the position for just two innings in 2012.
"I played on the left side of the infield my whole life," Kinsler said. "Until Triple-A, I played shortstop. It's very similar. And I have two [Major League] innings under my belt -- so I'm a seasoned vet."
Camp notes
• Luis Perdomo and Pedro Avila were among those who faced hitters during live batting practice Monday. Perdomo is fighting for a role on staff as either a multi-inning relief option or a back-of-the-rotation starter. On Monday, his efforts seemed focused on his slider, a pitch that he said could see an uptick in usage this year.
Avila, meanwhile, is the Padres' No. 29 prospect according to MLB Pipeline, and he's in his first big league camp. He faced established big leaguers Austin Hedges, Travis Jankowski and Manuel Margot -- a few times apiece -- and he allowed only one clean hit, a Margot single.
• Closer Kirby Yates was scratched from his scheduled bullpen session Monday, and he was sent home while he recovers from a head cold. The illness is unlikely to throw a dent into his progression plans.