There’s a saying that goes, “Don’t buy free agent pitchers. Pitchers, who are more arm and shoulder demanding than hitters, are often in their prime before they hit free agency. After signing a free agent contract, they often go downhill due to injuries and declining pitches.

Doosan left-hander Jang Won-jun (39), who announced his retirement from active duty on Aug. 28, is a rare pitching free agent success story in KBO history. The rare case of a late-20s free agent starting pitcher leading a team to back-to-back championships as soon as he arrived is unlikely to be seen often in the future.

Jang Won-jun, who joined Lotte in the first round in 2004 after graduating from Busan High School, has been a 10-win pitcher since 2008. He grew from a soft delivery to a mid-to-high 140s fastball, a sharp slider, and good command. He hit free agency in 2014 after six consecutive seasons of double-digit wins with Lotte. His market value skyrocketed as a 29-year-old pitcher with durability and no major injuries.

Despite a four-year, 8.8 billion won offer from his original team, Lotte, Jang went to Seoul. Doosan, which had been slow to sign outside free agents, paid a hefty 4.84 billion won for Jang Won-jun. When he moved to Doosan for less money than Lotte, there were speculations of a six-year contract. The officially announced 8.4 billion won was the highest amount for a pitcher at the time, making it Doosan’s first outside free agent signing other than Hong Seong-heon, who was originally from Doosan.

In his first year as a free agent, Jang proved his worth. In 30 games (169⅔ innings), he went 12-12 with a 4.08 ERA. That year, Doosan finished third in the regular season and started the semi-playoffs, but by the Korean Series, Jang had emerged as a big-game pitcher, going 3-0 with a 2.36 ERA in four games (26⅔ innings). Doosan also won the Korean Series upset, marking the beginning of a dynasty.

In 2016, Jang went 15-6 with a 3.32 ERA in 27 games (168 innings). He finished the year with the second-best ERA in the league. The team also won the Korean Series, clinching the NC in Game 2. Doosan swept the regular season and Korean Series, and Jang was at the center of it all.

As of the Korean Series, Jang is the only pitcher to win back-to-back titles after signing as a free agent. The only other player to do so is infielder Park Jin-man, who led Hyundai to the 2005 and 2006 championships after joining Samsung. 굿모닝토토 도메인

Jang Won-jun had an exceptional 2017, going 14-9 with a 3.14 ERA in 29 games (180⅓ innings) to lead Doosan to the Korean Series. While the team ended up as runners-up to KIA, Jang had an impressive pitching matchup with Yang Hyun-jong, who tossed seven scoreless innings of relief in Game 2.

His last peak came in 2017, when he posted double-digit wins for eight consecutive seasons. From 2018, his performance plummeted due to a decline in his pitching, and he signed a regular salary contract every year since 2019, when his four-year free agency contract ended. He received 1 billion won in salary during his four-year free agency period: 600 million won in 2019, 300 million won in 2020, and 80 million won in 2021.