MILWAUKEE -- In a move that changes the look of the Cardinals' rotation for the stretch run and paves the path for a youth movement in 2018, the Cardinals dealt veteran starter Mike Leake to Seattle for Minor League shortstop Rayder Ascanio on Wednesday. The Mariners are also receiving $750,000 in international cap space as well as cash considerations.
Leake, who helped finalize the trade by waiving his no-trade clause on Tuesday, is owed $48 million over the next three seasons as part of the five-year contract he signed in December 2015. He also holds an $18 million mutual option with a $5 million buyout for '21.
According to sources, the Cardinals agreed to send the Mariners $17 million to help cover part of that remaining cost. Clearing the rest of Leake's salary off the books will offer the Cardinals additional financial flexibility to help the team address various holes this winter.

As far as filling the rotation void, however, the Cardinals are prepared to do that from within. Jack Flaherty, the organization's No. 3 prospect per MLBPipeline.com, will step in to take Leake's spot for now, manager Mike Matheny announced after Wednesday's 6-5 loss to Milwaukee.
Flaherty will make his Major League debut on Friday in San Francisco.
"The development side has produced a lot of live arms, and we're certainly excited to see what they're capable of doing," said Cardinals president of baseball operations John Mozeliak. "Ultimately, we got to a point where we thought [the trade] was best for [Leake], best for the Cardinals and best for some of our young players to have this opportunity. That's what really pushed us over the top to do this."

With Carlos Martinez, Michael Wacha and Adam Wainwright under contract next season, removing Leake from the mix will give the organization an opportunity to give young starters a chance to fill the other two holes. Mozeliak mentioned prospects Luke Weaver, Alex Reyes, Flaherty, Dakota Hudson and Sandy Alcantara as players ready to solidify themselves at this level.
"If we're trying to sort of reshuffle the deck this offseason, this was a rare opportunity for us to try to do something now rather than wait," Mozeliak added. "I think from a manager standpoint, from a pitching-coach standpoint, they all understood that if we were able to do this, it was in the best interest of the big picture."
One pitcher Mozeliak did not include in his list of possible replacements was Lance Lynn, who will be a free agent at the end of the season. The Cardinals have not engaged in discussions with Lynn about a potential extension, and the right-hander is expected to command more than the $80 million contract Leake received two years ago.
It did not sound as if Wednesday's move would reignite the organization's interest in trying to re-sign Lynn.

"I don't think I would draw any conclusions by what we did today to determine what we're going to do in the offseason in that regard," Mozeliak said. "But clearly, when you look at our young pitching coming, we feel like that's our strength and that's our future."
The lone player coming back to the Cardinals in this deal is Ascanio, a 21-year-old switch-hitting shortstop who has been in the Mariners' system since he signed out of Venezuela in 2012. Ascanio hit .217/.295/.355 with a .649 OPS in 111 Minor League games this season, and he will be added to the Cardinals' Class A Advanced Palm Beach roster for the remainder of this year.
As for Leake, he heads into the middle of an American League Wild Card race while also trying to get his season back on track. Since opening the year with a 1.91 ERA in nine starts, Leake has posted a 5.73 ERA in 17 appearances. The Cardinals nearly removed him from the rotation last week, but they decided to give him another start to help sustain his trade value.
"I'm just excited to be heading to be part of the Mariners," Leake said shortly before boarding a flight out of Milwaukee. "It's been a whirlwind, but it's nice to be coming to a new team with a fresh start. It's a team I've always paid attention to because I grew up a Mariners fan, and now that I get a chance to put their uniform on and represent this team, it's a huge thing for me and my family."