Reminder: Always double check the lineup card before rosters lock to make sure that a player you've chosen to roster is playing that day, and check the weather to make sure your players won't get rained out of their game.
In the early game, a guy I think presents a high upside gamble is Robbie Ray ($6,400). The Cubs have the highest K% in baseball vs LHP at just under 26%. Ray's above average 21.2% K%, combined with the swing and miss in the Cubs lineup, makes a high strikeout total more likely. The Cubs have the 6th worst wRC+ vs LHP on the year at 87, so they haven't been productive vs lefties as a team, either. Ray's handedness also largely neutralizes rookie stud and crusher of baseballs Kyle Schwarber, who has struggled vs LHP early in his MLB career. Ray also provides gigantic salary relief to load up elsewhere. The main issue with starting Ray is that his opposition is Jake Arrieta, making it difficult for him to get run support.
In the late game, Lance McCullers ($9,000) and his 25% K% take on the Twins in Houston. The Twins have the 6th highest K% vs RHP at 21.5% and the 4th worst wRC+ vs RHP at 89. Ervin Santana, who has struggled after testing hot for PEDs, opposes McCullers, making run support more likely. George Springer has also just returned to the Astros lineup.
Chris Young ($3,100) vs Matt Moore
Young has a 173 wRC+ and .274 ISO vs LHP this year and usually bats in a good slot in the lineup against lefties. Moore has struggled in his return from Tommy John surgery.
Brandon Belt ($4,500) vs Chad Bettis
Belt has hit RHP to a 137 wRC+ and .204 ISO this year and significantly more of his home runs have come on the road away from San Francisco's pitcher friendly park (13 HR on road, 4 HR at home this year, and career 43:19 ratio). Belt gets the best road park imaginable today, Coors Field.
Matt Duffy ($2,900) vs Chad Bettis
Duffy has hit RHP to a 134 wRC+ and .150 ISO, and the matchup takes place in Coors Field.
Rougned Odor ($3,500) vs Jered Weaver
Odor, always a talented prospect, exploded after a demotion to the minor leagues in May: in 248 PA since being recalled, he's hit to a .330/.364/.570 slash with a .239 ISO. Odor has been dealing with a finger injury that kept him out of the lineup for a few days, but he says he feels good at the plate. Weaver has allowed a .281/.326/.502 line to lefties this year and is averaging 85 mph on his fastball.
You can follow me on twitter at @TimFinn521