This offseason, we’re looking at the Mets’ history with free agency. We’ve highlighted four pitchers so far, one of which is heading for Cooperstown and another who’s already there. Next is another pitcher who also has a Hall plaque who was one of the greatest pitchers of his era before arriving in New York.

It’s not about what he did, it’s about what came after him.

Pedro Martínez was, in many ways, a precursor, to Max Scherzer: a three-time Cy Young winner and Hall of Fame-bound pitcher on the back end of his career who portends future significant acquisitions.

Martínez was 33 and coming off a curse-breaking World Series title with the Boston Red Sox. The best days, at times historically great, were clearly in his past. But Mets fans were definitely granted glimpses of vintage Pedro, especially in 2005 — which turned out to be his only great season in New York.

The most significant effect of the signing was that it rejuvenated a fan base that had seen three dreadful seasons in a row and created an influx of talent that followed him, most notably Carlos Beltrán later that offseason. It’s a guarantee that without Pedro, there would be no Beltrán.

The first major deal for general manager Omar Minaya, at four years and $53 million, brought instant credibility for an organization devoid of such credit. And Martínez’s presence on the mound created a buzz around his starts, especially at Shea Stadium.

Even though he had yet to reach his mid-30s, Martínez — with a slight frame that belied his overpowering stuff — had logged 200 or more regular season innings in six of the past eight years (not counting his multiple playoff appearances). Yet he was able to throw 217 more in 2005, the name number he tallied in ’04.

In another All-Star season, Martínez had a league-leading 0.95 WHIP — the sixth time he led his league in that category and the fifth time he led the majors. Martínez won 15 games with a 2.82 ERA and 208 strikeouts. He tossed four complete games, the most for him since 2000, and topped all Mets in WAR. At 7.0, that number ranks tenth all-time in franchise history for pitchers.

His outing on September 16 at Shea Stadium may have been his best of the year, one in which Pedro fanned struck out 10 Atlanta Braves to highlight a complete-game shutout.

As the Mets improved their roster for 2006, acquiring Carlos Delgado in a trade with the Marlins, Martínez wasn’t able to maintain the zip on his fastball as the year progressed. The disparity between his heater and his curveball lessened and making him less effective than in his heyday.

He was again an All-Star but he soon was not the same Pedro from even a year ago. Injuries, to his right calf and his shoulder, were the main culprit. By the end of May, he had 88 strikeouts and a 2.50 ERA. After that, his ERA was 7.10. As the Mets cruised to the NL East crown, his presence in the rotation as October would have still been invaluable, especially if he was healthy. Unfortunately, he wasn’t. Martínez’s shoulder kept him out the postseason. It would be almost a year until he returned to the mound.

He made five starts at the tail end of the 2007 season and pitched to a 2.57 ERA, giving hope he could sustain this level the following year. But a strained hamstring in April put him out for over two months. He would finish out his Mets career with a 5.61 ERA over 20 starts before joining the Phillies for 2009.

Pedro Martínez initiated a new era for the Mets. Even if it wasn’t the pitcher who dominated with the Expos or Red Sox, his charisma brought about a certain excitement, not to mention other players who wanted to be part of the fun. Some signings wind up being more about the player’s appeal than the player’s performance. And that was certainly the case here.