The Marlins acquired the 32 year-old LHP from the Tigers at the end of spring training, and the Tigers are paying 9.6 of his 10 million dollar salary. He was drafted by the Marlins back in 1999 in the 5th round and was traded to the Tigers in 2003. For his career, he has a 5.17 ERA and 1.47 WHIP. He's only struck out 6 per 9, and walks 3 per 9. He's been a below average pitcher over the course of his career. He has had a myriad of injuries (he was on the DL twice last year, with a lower back strain in May and elbow surgery in July), and also had off-season groin surgery. Last year he had a 5.44 ERA and 1.75 WHIP in only 49 innings, but had a 3.77 ERA in his 29 innings after his July surgery. He's faced the Mets four times, is 2-1, and has a 4.30 ERA and 1.74 WHIP.
Robertson is mainly a three-pitch pitcher, featuring an 88-mph fastball, a slider and a change-up. His 81-mph change-up was his best pitch last year, but none of his pitches have been plus this year. He occasionally throws a curve-ball. He has starting throwing a 2-seam fastball this year and it has been his best pitch (throwing it 30% of the time).
When he faced the Mets on May 15, he was 3-3 in his 7 starts, throwing 35 2/3 innings, with a 4.54 ERA and 1.57 WHIP. He had only gone 6+ innings twice in his seven starts. In his first start versus the Mets this year, he went five innings, allowed one run on six hits and no walks, striking out four. He was walking > 4.5 W/9 this year, which was very high for someone who doesn't strike people out (5.8 K/9). On May 15th, he got the win, lasting 5 2/3 innings, scattering seven hits and walking one, allowing two earned runs, while striking out two. He had three starts since that meeting and twice let up four earned runs. On June 5th he faced the Mets for the 3rd time and the Mets finally figured him out, pounding him for six runs in 4 2/3 innings, including D Wright's second HR of the year off of him.
For the year, Robertson is 5-6, with a 4.89 ERA and 1.50 WHIP. He has a terrible swing and miss rate (6.5%), strikes out < 6 K/9, and walks too many (3.7 W/9). He's minimized home runs (7 in 77 innings), or his ERA could be even worse.