PEORIA, Ariz. -- The Padres' bright future is rapidly becoming the present, and Tuesday presented the clearest evidence yet: Manny Machado is headed to San Diego.

The superstar free-agent infielder agreed to a deal with the Padres on Tuesday morning, sources have told MLB.com. The agreement is for a record $300 million over 10 years with an opt-out after five years and a partial no-trade clause, a source confirmed to MLB.com's Mark Feinsand. It's the largest free-agent deal in the history of American sports, surpassing the 10-year, $275 million contract that Alex Rodriguez signed in December 2007.

The Padres have not yet confirmed the signing, which is pending Machado's physical. Despite multiple reports of an agreement, Padres executive chairman Ron Fowler said, "We do not have a deal. We are continuing discussions." It's standard practice for the Padres not to comment on such agreements until they are finalized.

At his annual Cactus League media day session, general manager A.J. Preller avoided questions about the deal, but he spoke glowingly of Machado's skill set.

"It's no secret, Manny Machado's one of the best players in baseball," Preller said. "He's a guy that handles both sides of the field. He's an elite offensive player and an elite defender, so he's obviously a guy that can help any club."

The move, once final, would fill the Padres' third-base void, seemingly the only remaining question in the club's long-term lineup. San Diego also boasts the best farm system in baseball -- a system that includes top shortstop prospect Fernando Tatis Jr., presumably Machado's partner on the left side of the infield for a long time.

"That would be awesome," Tatis said, breaking out into a wide smile upon hearing the news. Padres fans everywhere can nod in agreement.

San Diego was in dire need of a middle-of-the-order bat, and Machado clearly provides that thump. He batted .297/.367/.538 with 37 homers last season. The Padres haven't had a hitter with 30-plus homers and a .900 OPS since Adrián González in 2010.

Machado also fills the biggest area of long-term need. Third base was the most pressing question mark.

As things stand, it's possible Machado opens the season at shortstop -- also an area of need, as Tatis isn't expected to arrive in the Majors until at least a few weeks into the season. But the Padres have been adamant about Tatis being their long-term shortstop, meaning that Machado, who spent his first six seasons at third before shifting to short last year, is likely bound for the hot corner once again.
The deal comes on the one-year anniversary of Eric Hosmer's previous franchise-record-setting $144 million contract. Machado will presumably fill out a long-term infield that features Hosmer, prospect Luis Urías at second and Tatis at short. Here's how that lineup could look, with every player mentioned below under contract for at least the next four seasons.

Urias, 2B
Tatis, SS
Hosmer, 1B
Machado, 3B
Wil Myers, LF
Hunter Renfroe/Franmil Reyes, RF
Manuel Margot/Franchy Cordero, CF
Austin Hedges/Francisco Mejia, C

In 926 career games over parts of seven seasons, Machado has 175 home runs, 513 RBIs and a .282/.335/.487 slash line. He has played in all but 11 games over the past four seasons, more than any other player in baseball over that span.
Machado brings elite defense to the table as well. He won two American League Gold Glove Awards with Baltimore, and has regularly ranked as one of the sport's best third basemen.
In every single facet, Machado makes the Padres a better team. It remains to be seen just how quickly he expedites the arrival of their window to compete in the National League West, as the rotation remains a major question mark. But the focus has clearly shifted toward contention.

"There's different ways to build a club," said Preller. "If the right guys are out there, guys that fit in the long-term plan, we want to add the right piece at the right time."
The Padres' ownership group, led by Fowler and general partner Peter Seidler, was on hand at Spring Training camp on Tuesday and addressed the media. Fowler made it clear that no deal had been finalized, and the duo couldn't confirm the news. But they're undoubtedly willing to put their chips in.
"Ron and I -- we love the city of San Diego, we love sports in San Diego, we're also well aware of the history," Seidler said. "There's never been a championship. ... We as an organization, we want to completely change that. We want our franchise to win year after year after year. And we're going to do whatever we can rationally do to help make that happen."
When asked why now might be the time to make a play for one of the top free agents, Fowler said: "There's no perfect timing. ... But there's not talent out there that becomes available every year that's as good as what we think is there now. We need a third baseman, obviously, and that's one of the reasons why those discussions started taking place. But we're not in a place where we can announce anything."
The Padres were also rumored to be after free-agent outfielder Bryce Harper, but those conversations will presumably end, now that Machado is on board. The Phillies, White Sox and Yankees were also in the mix for Machado's services.
Machado was drafted by the Orioles with the third pick in the 2010 Draft -- two picks after Harper. He debuted with Baltimore on Aug. 9, 2012, and he earned his first All-Star berth and Gold Glove Award the following season. (The Padres play two games in Baltimore this season -- June 25-26.)

In every full year Machado has played, he would've led the Padres in wins above replacement. But last season, he posted the best statistical year of his career, doing so amid constant trade talk and a position change. He was dealt to the Dodgers in July.
Machado created some unwelcomed headlines during the NL Championship Series, telling FOX Sports' Ken Rosenthal, "I'm not the type of player that's going to be 'Johnny Hustle,'" responding to criticism about not running hard on the bases. Machado clarified the comments in November during an exclusive interview with MLB.com.
"When I was asked that question, I was definitely on the defensive, and I was wrong to answer it the way that I did, because looking back, it doesn't come across how I meant it. For me, I was trying to talk about how I'm not the guy who is eye wash. There's a difference between fake hustle for show and being someone who tries hard to win. I've always been the guy who does whatever he can to win for his team."

His team, to the surprise of many, is now the San Diego Padres. And, predictably, his new teammates are thrilled about that. They learned of the news as they exited the practice fields at the Peoria Sports Complex following the first full-squad workout of the spring on Tuesday.
"He's a game-changing player," Hosmer said. "He's extremely talented. He brings that edge. We got to see what he did the last part of last year in L.A. We'll be glad to have him on our side now."
"In our meeting today, as we started, we talked about how starved this city is for wins," said Hedges. "That's what we expect to give them. Obviously the front office is making moves to help make that happen."