Cameron suffered the injury in the seventh inning of Sunday's 7-3 loss to the Rockies at PETCO Park when left fielder Milton Bradley stepped on his right hand as both players pursued a Garrett Atkins' inside-the-park home run.
Cameron said there's no specific timetable for how long he'll be out, though the doctor who saw him Monday morning gave him a window of two weeks to a month. Cameron isn't so sure he couldn't return for the playoffs, though.
"It didn't really look good yesterday and I can't really move it right now," Cameron said. "But I've always been a quick healer. But it's in a spot where you just don't know. I can run, that's about all I can do right now. If I go out there, I'm taking a chance where it can get hurt more."
The news was especially crippling since the Padres on Monday were also informed that Bradley tore the anterior cruciate ligament in his right knee in a bizarre incident during the eighth inning Sunday.
Those two injuries set about a roster shift on Monday as Minor League infielder Chase Headley and outfielder Drew Macias were added to the roster. The Padres also made a trade, acquiring 30-year-old Jason Lane from the Astros for a cash considerations or a player to be named later.
"With two potential free agents in Cameron and Bradley, it's nice to have him [Lane] for the next six days and we control him over the winter. He's another guy to put in the mix with [Scott] Hairston and [Brian] Giles," Padres general manager Kevin Towers said.
Lane was hitting .178 with eight home runs and 27 RBIs for the Astros, though he hit 26 home runs two seasons ago. Lane can play left and center field.
"He had a good year a couple of years ago. This year, things haven't quite gone his way. He has tools, he can run for a big man, plays a good outfield, had right-handed power. He's not hitting for the average that I'm sure he or the Astros expect. Maybe a change of scenery and a short window might help," Padres manager Bud Black said.
Lane, Hairston and Terrmel Sledge will likely see the most time in left field, though Lane will also play center field as will Brady Clark, who started there on Monday against the Giants.
Heads still high: The news that Bradley and Cameron will be lost for the rest of the season certainly wasn't welcomed in the Padres' clubhouse on Monday, although two of the team's most outspoken players -- pitchers Trevor Hoffman and Jake Peavy -- said the team will press on.
"People are faced with adversity throughout the season in different stages. Obviously it's two pretty big blows but I don't think there's anything we can't handle in the short term," Hoffman said.
Peavy said the Padres are going to embrace the us-against-the-world mantra and that some have discounted the team from postseason contention because of the recent three-game losing streak and the loss of Cameron and Bradley.
"We're going to try and rally around the fact that the odds are stacked against us," Peavy said. "We'll go out and play hard. We're certainly going to miss Mike and Milton and what they bring to the team, offense, defense ... everything. We can have a good week with those two guys [Clark, Hairston and others] in there."
So who is Macias? When the Padres opted to dip into their Minor League pool of players on Monday, they chose Macias, a 24-year-old who hit a combined .259 during the past season with Double-A San Antonio and Triple-A Portland.
Macias, a left-handed batter, had 10 home runs and 61 RBIs in 131 games. He will likely be insurance during the final week of the season.
Headley, the Texas League Offensive Player of the Year at San Antonio, will be making his second tour of duty with the Padres. He appeared in seven games in June, hitting .176 in 17 at-bats while Kevin Kouzmanoff nursed a shore back.
Friar notes: San Diego's relievers have posted a 0.98 ERA over their last 36 2/3 innings, a stretch that spans nine games. There was a consecutive innings streak of 24 scoreless innings during that stretch. ... Kouzmanoff needs one home run to set the team's rookie record for home runs (18), which was set by Benito Santiago. ... Josh Bard has collected two or more hits in five of his last six games since Sept. 16 and is hitting .579 in that stretch.
On deck: The Padres play the second game of their three-game series against the Giants at 7:15 p.m. PT on Tuesday. Brett Tomko (4-11, 5.36) will get the start for the Padres. Matt Cain (7-16, 3.68) will start for San Francisco.