In return for Leake, the Reds received two prospects, right-hander Keury Mella and infielder Adam Duvall.
The 27-year-old Leake has not been the best Reds' pitcher to be involved in trade rumors, with Johnny Cueto being moved earlier this week, but he has received a lot of buzz recently, considering his price isn't huge and he is still a serviceable starter.
The Giants have needed pitching, especially starting pitching, to help them down the stretch run. They rank 24th in the Major Leagues in fWAR from their starters, including not so great FIP (3.97) and xFIP numbers (3.93).
Leake, a free agent at the end of the season, is 9-5 with a 3.56 ERA (3.88 FIP) in 21 starts this season. Over 136 2/3 innings pitched, Leake has worked to a 90 to 34 strikeout-to-walk ratio.