After the Marlins signed Wei-Yin Chen in January, they were reportedly still seeking another veteran starter to add to their starting rotation. As the club prepares to enter March, the starting rotation appears to be the biggest area of concern.
There is nothing to be concerned about in the front end of the rotation. Jose Fernandez, as long as he can remain healthy, is one of the most dominant pitchers in baseball. Beyond him, though, there are some questions that have to be answered.
Miami was able to add Chen in what was probably one of its bigger off-season moves. Chen had a notable amount of success pitching with the Orioles in the American League East and has posted consistent numbers when facing left-handed hitters throughout the course of his career.
Right-handed hitters have a career .457 slugging percentage against Chen, and there are quite a few right-handed power bats in the National League East. Chen will almost certainly have success more often than he struggles in 2016, but his numbers against righties and number of home runs he allows will be things to monitor.
Tom Koehler seems to have a rotation spot locked and the same could be true for Jarred Cosart if he has success and is healthy this spring. The winner of the competition for the final roster spot could dictate how well the Marlins perform this season.
Edwin Jackson appears to be the early favorite, and pitching guru Jim Benedict has had his way with altering pitcher deliveries in the past. But Jackson has lost a combined 33 games as a starter over the last two seasons and has not posted an ERA under four as a starter since 2011.
If the Marlins feel Jackson is better suited for a spot in the bullpen, they might have to turn to one of their prospects. Justin Nicolino and Adam Conley both have experience.
Chris Narveson and Dustin McGowan highlight the Marlins' list of non-roster invitees who could make the roster, but the Marlins are more likely to turn to their internal depth.
Miami might still consider adding depth, with Alfredo Simon, Kyle Lohse and Tim Lincecum on the market. But until a move is made, the starting rotation remains the club's biggest weakness.