Gary A. Vasquez/USA TODAY Sports

After months of speculation and stalling, the Red Sox finally agreed to terms with the #1 free agent power hitter on the market. J.D. Martinez signed a 5-year, $110 million contract with the Red Sox on the first day of full squad workouts in Fort Myers. The contract was less than the original asking price and is front-loaded with 2 built-in opt-outs, which makes it reasonable (if that’s possible) for both parties involved. Beyond the dollars, the bigger question is around impact. Does J.D. Martinez help to make the Red Sox a serious contender in 2018? The short answer is yes…but.

Let me start by saying that I could just as easily see J.D. Martinez flourish in the friendly confines of Fenway Park as I could see him take a nose-dive into the Charles River. He’s one of the harder hitters to figure out, in my opinion, because he doesn’t have a long history of success. Everyone has been talking about his huge 2017, but 29 of his 45 HRs came in just 62 games after being traded from the Detroit Tigers to the Arizona Diamondbacks. That’s a tremendous stretch, but the likelihood he has another stretch even close to that in his career is very low. I look at 2017 as being a bit of an anomaly for J.D., but did display his raw power potential. The Red Sox brought him in as a middle-of-the-lineup power bat, but will he produce like a middle-of-the-lineup bat?

The positives first. In 3 full seasons with the Tigers (2014 through 2016), Martinez averaged 134 games played, 551 plate appearances, .299 average, .357 slugging percentage, 28 HRs, and 82 RBIs per year. By any account, those are really solid numbers for a power bat in the 3-5 hole in the lineup. If that’s the J.D. we see in Boston, I think most fans would be happy with his performance. For perspective, the Red Sox won 93 games in 2017 without having a single player hit more than 24 HRs (24 – Mookie Betts) and just 1 player with a higher slugging percentage (.369 – Dustin Pedroia). Given those averages, J.D. would be the best hitter in an already strong lineup.

On the negative side, there are definitely some consistency concerns. Of the 3 full years in Detroit, J.D.’s power was inconsistent, hitting  23 HRs in 2014, 38 in 2015, and just 22 in 2016. He played in 158 games in 2015 compared to 123 in ’14 and 122 in ’16, but that’s a huge 15-16 HR swing year-to-year, even with more at-bats. If the Red Sox get ’14 or ’16 Martinez, that’s concerning. The Red Sox don’t need another 20-25 HR hitter in the lineup (they had 4 in 2017), they need a feared 30+ HR hitter who can lift the pathetic overall team power out of the basement.

Age is another factor I’m concerned about. According to an Alex Speier article  in the Boston Globe looking at age correlation with offensive power in January 2015, “…after turning 30, players experience a clear and steady decline in the likelihood they’ll be productive offensive contributors.” The article looked at WAR (Wins Above Replacement) and it showed a 50% decrease in 33-year old players delivering a 2.0 WAR that players aged 26-29. What does this all really mean? J.D. may be in later part of his peak and have a few strong power years left, or he could be primed to start sliding down the backside of the hill in 2018.

The other less concerning piece for Martinez is his streaky nature, which is not uncommon with power bats. Taking 2015 as an example, he hit 14 of his 38 total HRs in a 20-game stretch in June and July, hitting just 4 in his final 34 games of the season. I imagine some of the late season struggles were around playing in 158 games, by far the most of his career, making it a lesser overall concern. The Red Sox will likely mitigated some of this by giving Martinez rest  when splitting some time with Hanley Ramirez in the DH spot. His other massive power streak, mentioned above, came last year when he hit 29 HRs in 62 games with the Diamondbacks.

My overall approach is cautious optimism. The Red Sox desperately needed to add a power bat to the lineup given their struggles in that department in 2017 and they got the best power bat available on the market without depleting their thin prospect system. It’s hard to argue against that. In addition, they need several players on their roster to have better 2018 results than 2017, Xander Bogaerts and Mookie Betts at the top of the list, but if 2015 or 2017 Martinez is in the lineup most nights, the pressure will be reduced on everyone else and the Red Sox could be legitimate contenders in 2018.