When the 2016 season starts, Johan Santana will be 37 years old. The lefty has not thrown a pitch in a major league game since August 17, 2012. But after a string of injuries disrupted his previous attempts to return to a big league mound, the two-time Cy Young award winner is again trying to come back in 2016.

Signed by the Houston Astros as an amateur free agent in 1995, Santana was taken in the 1999 Rule 5 draft and traded to the Twins that day. To guarantee they could keep Santana for the long term, the Twins had to leave Santana on their active roster for all of the 2000 season, and they did—despite Santana's struggles. In 30 appearances, five of which were starts, Santana had a 6.49 ERA.

The following year, Santana made just 15 appearances. He was a bit more effective in those than he had been in his rookie year, but his breakout season came in 2002. He split hist time between the rotation and the bullpen that year, and he finished the season with a 2.99 ERA and 2.66 FIP. He continued to pitch in both roles in 2003, another successful season, before he finally became a full-time starting pitcher in 2004.

From that season through 2007, Santana had a 2.89 ERA and 3.14 FIP, won the Cy Young award twice, and finished in the top five in Cy Young voting in each of the other two seasons. He struck out 9.7 batters per nine and walked just 2.0. Among qualified starting pitchers over those four years, Santana's ERA ranked second in baseball, and he trailed only Roger Clemens—who threw 275 fewer innings.

Before the 2008 season, the Twins traded Santana to the Mets for a package of prospects: Carlos Gomez, Deolis Guerra, Philip Humber, and Kevin Mulvey. The Mets were coming off a now-infamous collapse at the end of the 2007 season, and Santana was seen as something of a savior. He was nothing short of spectacular in that first year with the Mets.

In 234.1 innings over 34 starts, Santana had a major league-best 2.53 ERA. In the penultimate game of that season, with a playoff spot very much on the line, he threw a complete-game, nine-strikeout shutout against the Florida Marlins. A day later, the Mets missed the playoffs on the last day of the season for the second-straight year, but Santana certainly wasn't at fault for that.

That was Santana's fifth season in a row with at least 200 innings pitched, but he hasn't hit that mark since the 2008 season. He was still very good for the Mets in 2009 and 2010, with a 3.05 ERA in 54 starts in total, but he threw 166.2 and 199.0 innings in those seasons, respectively. And late in the 2010 season, Santana had surgery after he tore the anterior capsule in his left shoulder. As a result, he missed the entire 2011 season.

He came back in 2012, though, and looked pretty great early in the season. He threw a shutout against the Padres on May 26 that year and had a 2.75 ERA at the end of the game. And in his next start, on June 1, he went out and threw the first—and still the only—no-hitter in New York Mets history.

A popular narrative later that year was that the 134 pitches Santana threw in the no-no wrecked his season, but in six starts in June, he had a 2.77 ERA in 39 innings. He finished the month almost exactly as he started it, with a 2.76 ERA on the season. July and August were nightmare months, though. Santana gave up six or more runs in each of his five starts over those two months. He had a 15.63 ERA over that stretch, and after his last start in August—still the last appearance he has on a major league mound—he had a 4.85 ERA.

In early July, Santana had sprained his ankle on a play at first base. And while it took several months after his last start in August, Santana required surgery on his left shoulder again in late March, 2013, after he and the Mets' front office butted heads publicly over his conditioning in spring training. He attempted a comeback with the Orioles in 2014, but a torn Achilles tendon ended that attempt. This year, he had signed a minor league deal with the Blue Jays, but a toe infection ultimately ended that attempt.

Johan Santana may very well have thrown his last pitch in Major League Baseball. But it's pretty great that he's still trying to come back. If he succeeds, perhaps he'll finish his career as he started it, pitching out of the bullpen. And, hey, the Mets could use a left-handed relief pitcher in 2016.