This player has been a rock for the Red Sox

This story was excerpted from Ian Browne's Red Sox Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

During an early season fit of inconsistency for the Red Sox, particularly on offense, there has been a rock in the lineup doing his job day after day and week after week.

That rock is J.D. Martinez, who remains a force in his age-34 season and fifth with the Red Sox.

Martinez rode into Wednesday night’s game against the Astros with the longest hitting streak (18 games) and on-base streak (34 games) of his career. The hitting streak was the longest in MLB this season before it came to an end on an 0-for-3 night, during which he was robbed of a potential home run and just missed an infield single on a reviewed play in his final at-bat.

The on-base streak included the first 29 games of this season, which put Martinez in some unique company. The most recent Red Sox hitter to reach safely in each of his first 29 games of a season was captain Carl Yastrzemski in 1978 (33).

During the hitting streak, Martinez did his best to lift his team at a time when it needed it most, hitting .387 with a 1.077 OPS to go with nine runs, nine doubles, four homers, 13 RBIs and three walks.

For all the talk about the contract status of team leader Xander Bogaerts, who has an opt-out clause in his contract that he is all but sure to exercise, it should be noted that Martinez is also a free agent at season’s end.

Martinez has expressed hope that he can remain with the Red Sox beyond this season, and he has plenty of teammates who are hoping the same.

Much like Bogaerts, who does a lot behind the scenes in the clubhouse, Martinez gives the Red Sox what amounts to another hitting coach.

Not only does Martinez study his own craft relentlessly, but he knows the ins and outs of the swings of all of his teammates.

“J.D. is a really special teammate and a player and a hitter, and he’s helped me a lot throughout my career to be where I am,” said Rafael Devers, the most dangerous hitter on the Red Sox. “He knows my swing, so if I have any trouble or anything, he’ll come to me and say, ‘Carita, you need to fix this or you need to fix that.’ In here, I don’t know who else will know more about hitting than he does. He’s a very special teammate and player for me.”

Though Martinez is more of a prototypical No. 4 or 5 hitter, manager Alex Cora recently installed him as the No. 3 hitter, which puts him after Devers and in front of Bogaerts.

“He is who he is,” Cora said of Martinez. “He’s a game-changer, offensively. The way he goes about it, the process is outstanding. He detaches himself from the results. Even when he hits a home run, he’s on to the next at-bat. He studies that swing, what he did right, wrong, whatever, and he’ll correct it if he has to for the next one. Then he goes with his game plan and he executes. He doesn’t deviate from that. It’s very impressive.”