Durability, however, might be Leake's best ability, particularly as he joins a Mariners rotation beset by injuries. There is also a mutual option in play for the 2022 season which would earn Leake a $5 million buyout if the Mariners made a decision to cut ties with the veteran starting pitcher.
Seattle also acquires cash and worldwide slot money while sending 21-year-old middle infield prospect Rayder Ascanio to St. Louis.
The Mariners (66-67) are three games out of the second wild-card spot in the American League.
Leake on the season has an ERA of 4.21 in 2017.
"It made us feel good about the price point", Dipoto told reporters after the trade was announced.
"This is as much about the next three, potentially four years as it's about this next four or five weeks", Seattle general manager Jerry Dipoto said.
U.S. disrupts evacuation of IS militants in Syria
The U.S. officials spoke on condition of anonymity because they weren't authorized to talk to reporters. Lebanese officials say they are nearly sure the remains are of the soldiers.
This is the second pitcher the Mariners have acquired from the Cardinals this season. After posting a 62-47 record and 3.87 ERA in 168 appearances (163 starts) for the Reds, the right-hander has gone 18-29 with a 4.41 ERA in 65 starts between the Giants and Cardinals. But he has struggled since the All-Star break, going 1-5 with a 6.90 ERA in nine starts since July 14.
Leake has been ultra dependable since making his major league debut in 2010, starting 228 games, which trails only Dodgers star Clayton Kershaw (231) for National League starts over that period.
The deal fills an obvious need for starting pitching for Seattle. He has roughly $55 million left on the five-year, $80 million deal he signed in December 2015.
U.S. growth upgraded to 3 percent in second quarter
For the year a whole, I am now predicting real GDP growth of 2.2 percent, with 2.8 percent growth for the current third quarter. Spending by governments, which had grown 0.7 per cent in the initial estimate, was revised to a decline at a 0.3 per cent rate.
The 21-year-old Ascanio was hitting a combined.217 with nine home runs and 44 RBIs between stops at Class A Modesto, Double-A Clinton and Triple-A Tacoma.
NJ representatives won't hold grudge against Texas, promise to support Harvey aid
Harvey made landfall in Texas over the weekend and catastrophically flooded the Houston area. John Cornyn and Ted Cruz voted against the $51 billion Sandy aid package.