The Marlins actually had people sort of excited for them this year. Entering the season it looked like they might have a shot at a wild card spot. When the Nationals stumbled out of the gate it seemed somewhat feasible the Marlins could threaten for the top spot in the division. Instead they're in the basement again. The only team they're really competing with are the Phillies for the worst team in baseball.
As far as their offense goes they've actually have been exactly as bad as the Brewers this year. Each team owns an 85 wRC+ on the season which is the worst in baseball. The Marlins position player on whole have actually accumulated more fWAR than the Brewers' though. They've been worth 11.3 fWAR and the Brewers only 6.5. If you're curious the White Sox own the worst mark with a staggeringly bad 2.2 fWAR.
The Marlins pitching staff is right around the middle of the pack with 8.9 fWAR which ranks 17th in baseball two spots below the Brewers 10.1 fWAR. The Marlins rotation (4.17 ERA, 4.10 FIP, 5.2 fWAR, 24th in MLB) has been a good deal worse than their bullpen (3.51 ERA, 3.11 FIP, 3.7 fWAR, 6th in MLB). There is evidence of that in the guys they're putting on the mound in the first two games against the Brewers. Neither has even 20 innings at the major league level.
Giancarlo Stanton is about the only legitimate offensive threat the Marlins have. He is currently on the DL with a broken wrist which has impacted some of his numbers. He still owns a 265/346/606 slash line on the season with 27 home runs in 318 plate appearances. Those numbers are very impressive and would be even more so had he not missed so much time. Without him the Marlins are not much of an offensive threat.
Monday August 17, 7:10 pm CST: Matt Garza vs Justin Nicolino
Nicolino: 16.2 IP, 5.9 K%, 5.9 BB%, .302 BAA, 1.38 WHIP, 0.54 HR/9, 44.8 GB%, 4.86 ERA, 4.31 FIP
He throws a fastball (89-90), cutter, curveball, and change-up.
Tuesday August 18, 7:10 pm CST: Tyler Cravy vs Adam Conley
Conley: 18.0 IP, 12.2 K%, 6.8 BB%, .265 BAA, 1.28 WHIP, 1.50 HR/9, 39.7 GB%, 5.00 ERA, 5.27 FIP
He throws a fastball (90-91), slider, and change-up.
Wednesday August 19, 1:10 pm CST: Wily Peralta vs Tom Koehler
Koehler: 134.1 IP, 16.7 K%, 8.2 BB%, .234 BAA, 1.23 WHIP, 1.00 HR/9, 46.9 GB%, 3.68 ERA, 4.27 FIP
He throws a fastball (92-93), slider, curveball, change-up.
Statistics courtesy of FanGraphs