The Padres can't be this strong of a favorite against any team especially when facing an opponent's top pitcher. That's the case here. 

Dan Straily is back healthy. The Marlins are 5-0 in his five starts this season. Straily has given up two or fewer runs in each of his last four starts. Opposing hitters are batting just .204 against him. The Padres rank 29th in runs and 28th in batting average. They have been held to three or fewer runs in six of their last seven games and are 6-14 during their past 14 games at Petco Park when facing a righthanded starter. 

San Diego is minus its best hitter, injured Wil Myers. The Padres lack any kind of punch without him. Also on the DL is Frenchy Cordero, who was supplying some needed power and speed. 

Tyson Ross has been a pleasant surprise for the Padres providing a nice comeback story. But he's not better than Straily and certainly doesn't deserve to be rated as such a high favorite. 

The Marlins hold the Padres' number, too, having beaten them six times in a row.