Rodriguez slots into the Padres' system as its No. 14-ranked prospect, according to MLBPipeline.com. San Diego also sent cash considerations to Toronto, with Upton owed approximately $22 million through the end of next season. The Padres will cover all but $5 million of that, according to a report by MLB Network's Jon Heyman.
"He's played well for us in the last month or two, and that led to some other clubs having interest," Padres general manager A.J. Preller said of Upton. "Ultimately, it came down to, like all these things do, two or three teams that are serious.
"The Blue Jays stayed on the deal. We looked at a few different prospects, scouting the Blue Jays system and ended up agreeing on Hansel Rodriguez. The money component, too, was a part of it, and we felt like that was the best deal to make."
The 19-year-old Rodriguez boasts a fastball that sits in the mid-to-low 90s and touches 97 mph. His offspeed pitches, however, remain serious question marks.
But the Padres, who scouted Rodriguez three times in the past month, believe his slider can develop into an above-average pitch. In six starts with Rookie-level Bluefield this season, Rodriguez had posted a 3.06 ERA with 26 strikeouts in 32 2/3 innings.
"Ultimately, he separated himself a little bit from the pack for our group," Preller said. "And he was a guy that we could agree on."
Upton, who was acquired alongside Craig Kimbrel during the 2014-15 offseason, was one of San Diego's steadiest players this season. He's batting .256/.304/.439 and is one of just two players in the Major Leagues with at least 15 homers and 20 steals. Defensively, Upton has excelled since moving to left field, with nine defensive runs saved, the third-best mark in the Majors among left fielders.
"They took a chance on me in the trade," Upton said of his time with the Padres. "They gave me an opportunity to play. I walked into Spring Training, and … playing time wasn't automatic, I had to earn it. Obviously I did, got the chance to play every day again, and I'm kind of feeling like myself again."
Upton also served as something of a human highlight reel for the Padres during the first half, setting a franchise record with three walk-off homers in a season. In the process, he also robbed three dingers, recorded a straight steal of home and launched the longest Padres home run ever recorded by Statcast™.
All of that helped turn Upton's burdensome contract -- on which he is owed $16.45 million next season -- into a manageable one. With the Padres out of contention and looking to bolster their Minor League system, a trade has appeared imminent for the past month.
With a deal looming, Upton was held out of San Diego's lineup on Sunday and Monday. The trade puts Travis Jankowski in as the club's starting center fielder, with Alex Dickerson serving as the everyday left fielder. Dickerson homered in each of the past two games.
"The deal, in general, is three-pronged," Preller said. "We get the prospect that we liked in Hansel Rodriguez. We get some money flexibility that I guess we're going to be able to reallocate elsewhere. ... And we get an opportunity to let Alex Dickerson really go play."
It was unclear who the Padres will call up to take Upton's spot on the 25-man roster. That matter could be further complicated because the team is currently in Canada.
While top prospects Manny Margot and Hunter Renfroe would seem to be logical choices, Preller hinted he might wait until September callups to give them their first taste of the big leagues. Still, with Upton in Toronto, the Padres are clearly paving the way for their outfield of the future.
"We love everything Melvin did for us -- the way he played, how he defended the field, how he swung the bat," Padres manager Andy Green said. "But when we're looking at what we're going to do in the future, we want to give these guys a real look."
As for Upton, he is the first Padres position player to be dealt this season. Closer Fernando Rodney and starters Drew Pomeranz and James Shields were all moved in exchange for prospects earlier this year.
"Quite frankly, at this point in time, it's not like we've broken up a championship club," Preller said. "We haven't gotten to where we want to get to, and we're going to look at some other guys and see if they can get us there."
In that regard, Preller is true to his word. Since the start of June, he has used every avenue imaginable to acquire young pitching talent -- a haul that now includes Rodriguez, Anderson Espinoza (Pomeranz trade), Chris Paddack (Rodney trade), Adrian Morejon (international signing), Cal Quantrill (Draft) and Eric Lauer (Draft).
"We're starting to develop a nice group of pitching prospects," Preller said. "The system's obviously gotten a lot better here in the last month or two. As a group, you need numbers, you need depth, you need quality. That's what we're trying to build."