Miami Marlins outfield prospect Griffin Conine made his major-league debut Monday with the Marlins. Conine struck out in his lone at-bat in his first big-league contest. Conine, the son of former major-leaguer Jeff Conine, was a second-round pick by the Toronto Blue Jays in the 2018 MLB draft out of Duke University. He's a career .244/.344/.485 hitter in the minor leagues in 585 games. This season in Triple-A Jacksonville, Conine hit .268/.350/.475 with 19 homers and 68 RBI. He will likely get more playing time moving forward, as the Marlins don't have much to play for down the stretch. He is not one of the Marlins' top 30 prospects but could get a good look the rest of the season.

Seattle Mariners outfielder Randy Arozarena's three-run homer in Monday's 5-1 win over the Tampa Bay Rays was his first in August and only his second since being traded by the Rays on July 26. Arozarena's home run was his only hit in three at-bats. He is hitting .213/.331/.385 with 17 homers, 46 RBI, and 63 runs scored along with 20 stolen bases in 28 attempts. Arozarena's power-speed combination and modest OBP keep him in most lineups. However, fantasy managers find it harder to justify having him in their lineups during the worst season of his career.

Miami Marlins pitching prospect Adam Mazur earned International League Pitcher of the Week honors for his performance this past week for the Triple-A Jacksonville Jumbo Shrimp. Mazur pitched six shutout innings allowing just one hit with no walks and four strikeouts in his latest outing. Since joining Jacksonville, Mazur, the Marlins' No. 12 prospect, is 1-1 with a 4.74 ERA and 1.16 WHIP in four starts. In 19 innings pitched with the Jumbo Shrimp, he has 15 strikeouts with just two walks. Mazur made eight starts for the Padres this season before he was traded to Miami. He pitched to a 7.49 ERA in the majors this season and could get another look with Miami when rosters expand in September.

Minnesota Twins outfielder Matt Wallner hit his 10th homer in Monday's 10-6 loss to the Atlanta Braves, part of a 2-for-3 evening, including two runs scored. Wallner is hitting .271/.403/.612 with 26 RBI, 21 runs scored, and three stolen bases on the year. Daily fantasy managers should make Wallner a priority when facing right-handers, as he's hitting .277/.408/.625 with nine homers, and 24 RBI against him. He has been a solid fantasy asset over the last month and is a must-start in leagues that use on-base percentage as a category.

Tampa Bay Rays first base prospect Tre' Morgan is heating up in August for Double-A Montgomery. In his first five games since being promoted to Montgomery, Morgan has hit successfully in each contest. Overall in August between High-A and Double-A, he is hitting .400/.437/.646 with three homers and 18 RBI. The LSU product is the No. 11 prospect for the Rays. The 22-year-old is progressing nicely through the minors and alongside Xavier Isaac makes for a nice tandem of first-base prospects in the Rays' system.