Iguchi suffered the injury in the seventh inning of Thursday's 2-1 victory when he fell as he tried to avoid a ground ball hit by teammate Kevin Kouzmanoff while running to third base on a full-count pitch.
Iguchi was told to rest for four weeks, though he'll have a better idea of his timetable on Wednesday when his shoulder is reexamined. But Black indicated Iguchi will be out for "four to six weeks, minimum."
The Padres recalled infielder Craig Stansberry from Triple-A Portland earlier Friday. He was in uniform for Friday's game against the Mets. Edgar Gonzalez started at second base and will get the majority of starts there moving forward.
Overnight, a position that was one of the most stable for the Padres -- Iguchi had started all but five games at second base this season -- is in the hands of two players who offer neither the offensive nor defensive profile of Iguchi, who hadn't committed an error.
"Now we're going with Edgar and Stans ... guys who don't have a lot of Major League experience," Black said, "guys who have been around big league camp. They're going to get a chance to play in the big leagues. Edgar has got some at-bats lately, Stans will get some. It's a chance to prove what they can do on the biggest stage."
Iguchi had three hits on Thursday to lift his average to .259. After a rough April (.225), he hit .278 in May, with nine multi-hit games. He had settled in nicely in his first season as the Padres second baseman after signing a one-year deal in December.
"A steady, dependable player, intelligent player," Black said Friday, repeating many of the same things he said about Iguchi that he did during his December press conference. "He really knows how to play. He was very much a stabilizing force in the infield and plays the right way."
For Iguchi, it's his first trip to the disabled list since leaving Japan to play in the Major Leagues in 2005. He hasn't played fewer than 135 games in any of his three previous seasons in the Major Leagues.
Iguchi said he was initially unaware of the extent of the injury after the play occurred.
"There's a lot of adrenaline, it was a full count," he said. "I took off, it was when I got to third base that I realized I landed on my shoulder and when I felt my shoulder ... I felt a bump. I knew something was wrong."
Gonzalez has started games at second base, shortstop, third base and left field since he was recalled from Portland on May 12. He is a second baseman by trade, which likely makes the transition from Iguchi easier to digest for the Padres.
"It's not something you look forward to happening to a teammate," Gonzalez said of the injury to Iguchi. "Like every other player, you want an opportunity, but you don't want it to happen like this."