Trade rumors have the Seattle Mariners connected with Los Angeles Dodgers outfielder Matt Kemp. Kemp has six years remaining on an eight-year, $160 million deal. A trade for him would likely involve the Mariners throwing in some solid prospects in exchange for the Dodgers eating some of Kemp’s contract. This would be a significant move for the Mariners. The multi-tooled star comes with some major concerns, however.

In 2011, Kemp was one of the best players in baseball. After a disappointing 2010 season where he had a slash line of .249/.310/.450 with an fWAR of 0.1, Kemp produced a monster .324/.399/.586 line with a 168 wRC+ and 8.4 fWAR. He narrowly missed the fifth 40-40 season in baseball history, falling just one home run short.

The 2012 season was less kind to him. After playing at least 155 games in each season from 2008-11, Kemp missed 56 games with two trips to the disabled list related to a pulled hamstring. Additionally, he played through shoulder and knee pain after crashing into the outfield wall in late August. When he was on the field, Kemp managed a .303/.367/.538 line with a 146 wRC+ and 3.2 fWAR. In the offseason, Kemp had surgery on his shoulder.

His injury woes continued in 2013, as the surgically repaired shoulder bothered him along with his hamstring. As if that wasn’t enough, he injured his ankle on a play at the plate against the Washington Nationals in July. All told, Kemp played in just 73 games, posting a .270/.328/.395 line with a 103 wRC+ and -0.4 fWAR. The shoulder injury had a big impact on Kemp’s power production as he had a career-low ISO of .125, more than a 100 point drop from the previous year. For the second straight year, he stole just nine bases.

Given his injury history and inconsistent production, what kind of performance can the Mariners expect from Kemp?

From 2006 to the first half of 2012, Kemp totaled 19.8 fWAR. Since the second half of 2012 to the present, Kemp has been roughly a replacement-level player. In 595 plate appearances, he’s produced just 0.8 fWAR.

Of course, Kemp was a replacement-level player over the course of 668 plate appearances in 2010, and the next year he produced at an MVP level. However, that Matt Kemp was two years younger and had not suffered through a string of serious injuries. While Kemp has managed decent, though far from elite, production with the bat since 2012, his defense and baserunning have suffered greatly. Going forward, it’s a safe assumption that Kemp will not steal the 32 bases he averaged from 2008-11.

Furthermore, it’s probably unrealistic to expect Kemp to play center field on a regular basis. Defensive metrics have never loved Kemp, but 2013 was his worst year. According to UZR, he cost the Dodgers 16 runs in center despite playing just 73 games. DRS paints a similar picture of his defensive abilities.

What remains is a bat-first corner outfielder who may have trouble regaining his power stroke. As those who have watched Adrian Gonzalez may have surmised, shoulder surgeries are not kind to power hitters. The Steamer projection calls for a .271/.342/.464 line from Kemp in 2014, with a 125 wRC+ and 2.5 fWAR. He still has offensive ability, but I’d be shocked if Kemp can return to anything close to his 2011 form.

Trading for Matt Kemp is a flashy move, but it’s unlikely to bring much more than a solid player, not a star, and one that may come as a burden to the payroll, too.