This off-season was pretty quiet for the Red Sox.  They did hire a new manager, but besides resigning Mitch Moreland and Eduardo Nunez, the Red Sox did not make a big move until late February.  The Red Sox appeared confident in their roster until they signed J.D. Martinez on February 26th.  But there was a clear need for a home run hitter, something the Red Sox have lacked since David Ortiz retired.  The need grew larger after the Yankees acquired OF Giancarlo Stanton.

But with Martinez on board, the Red Sox may be able to compete with the Yankees in the AL East, a feat that appeared impossible after the Sox lost out on Stanton to their archrivals.  This year, the Red Sox-Yankees rivalry is back and better than ever.  Despite the fact that the Yankees have the Top 2 home run hitters of 2017 on board, the Red Sox have #3 in Martinez and he can help them compete along with a strong rotation.  That’s assuming that J.D. continues to hit dingers with the best of them.

Switching teams, especially to a big baseball city like Boston, adds pressure that can often impact results as it did for David Price.  Like I did last year on top pitchers who switched teams to make predictions for Chris Sale, I researched how MLB Top 5 home run hitters perform after changing teams the following season.  I only evaluated players traded or signed to start on a new team the season after they were a top 5 HR hitter.  This research could provide intel on what to expect for both Giancarlo Stanton and J.D. Martinez.  Since Stanton is a little younger than Martinez, could it show that he is more likely to remain elite?  Although it is hard to predict the age at which a player will decline, history has shown that for many players, performance begins to decline in their mid to early 30’s.

The Research

The “Baseball Bits”

• In the last 100 years, only 33 players have changed teams the year after completing a season as an MLB Top 5 home run hitter
  • Only 6 players (18.1%; these guys are highlighted green on the spreadsheet) have remained in the Top 5 in the following season
    • This has not happened since 2003 when Jim Thome did it after going from the Indians to the Phillies
  • 15 players (45.5%) remained in the Top 20 but fell out of the Top 5 (these guys are highlighted yellow on the spreadsheet).
    • In total, 21 of the 33 players (63.6%) have remained in the Top 20
  • 5 of the 33 players (15.1%) remained in the Top 50 but did not make the Top 20 (these guys are highlighted in orange on the spreadsheet), meaning that 26 of the 33 remained in the Top 50 (78.8%).
• Only once before has an MLB Top 5 home run hitter come to the Red Sox (Jimmie Foxx came to the Red Sox in 1936) the year after achieving the feat the year before, He remained in the Top 5 in Year 1 with the Sox.  However, this was back in the 1930s when there were less big home run hitters who could surpass him.
• Prior to Stanton, the Yankees had acquired two MLB Top 5 home run hitters who achieved the feat the year before on another team.  Babe Ruth, who came in 1920 as the Curse of the Bambino began, stayed in 1st place with the Yankees, hitting 25 more dingers than he had when he finished first with the Red Sox in 1919 (he had 115 more at bats in 1920).  Alex Rodriguez, who came from the Rangers in 2004, stayed in the Top 20 despite dropping out of the Top 5.
• Prior to 1970, big home run hitters were less common, keeping the same guys on top year after year.  In addition, switching teams was less common for a superstar back then and the off-season was not anything like what it is now.  Of the 9 top 5 home run hitters who switched teams the next year before 1970, 3 remained in the Top 5 but all 9 remained in the Top 20.
• Only 4 players have switched teams after a Top 5 home run hitting season more than once.  They are:
  • Adam Dunn: He remained in the Top 20 the first time he did it, but after heading to the White Sox, he declined, falling out of the Top 100 and hitting just 11 home runs.
  • Greg Vaughn: He stayed in the Top 5 after the first time, but after switching teams again the next year, just made the league’s Top 50 in home runs.
  • Albert Belle: He did this twice in the span of three years, and he placed between 15th and 30th in each of his first years after.  However, it only took one year for him to adjust the first time.  After a second time, he declined and decided to retire.
  • Rocky Colavito: He did this twice.  In his first year after, he stayed in the Top 20 both times, but did not make the Top 5 either time.  However, he took just one year to adjust in both cases.

The Verdict

It is hard to come up with a verdict based on this research alone.  But based on what I think and the research I have conducted, J.D. Martinez will fail to make the Top 5 again but will hit at least 30-35 home runs and make the Top 20.  Some people believe that he could turn out like Jason Bay did for the Sox, but I don’t think that is the case.  Based on the research, I think Martinez is a better player (Bay never made the Top 5).

Since 2014, Martinez has been a consistent HR hitter and I find it hard to believe that he will decline too severely after joining the Red Sox.  He’s not 35, he’s still just 30 years old.  If he does struggle, I think he could easily bounce back in Year 2 or 3.  As for Stanton, I think he will stay in the Top 10 if not the Top 5 with at least 40 dingers.  He is only 28 and people are talking about him and Aaron Judge as having the potential to become a historic home run hitting duo.

Speaking of rebounding in Year 2 or 3, I think that after a strong Spring Training, David Price could bounce back.  He won’t be quite what he used to be but he will at least put up a strong season that will put him back in the conversation when it comes to elite starters.  With Opening Day tomorrow, comment with your Red Sox thoughts.