Nathan's Improbable Minor League Journey

The San Francisco Giants started Joe Nathan's professional baseball career by making him a sixth-round pick in the 1995 MLB Draft. Nathan played his high school and college career as a shortstop and he became only the second player ever selected out of Stony Brook University. It was a humble beginning for who would become one of baseball's all-time best closers.

Nathan began his professional career as a 20-year old in Low-A. In 56 games, he hit .232/.320/.345 with 12 extra-base hits. He struggled on the defensive side of the ball by committing 26 errors in 252 chances (.897 fielding percentage). The Giants had seen enough, as this would be Nathan's lone professional season at shortstop. He would spend the 1996 season transitioning to the pitching mound.

Transitioning To The Mound

His pitching debut would come a full season later (1997) at the Low-A level where he split time as a starter and a relief pitcher. He posted a very good 2.47 ERA but his other numbers showed he was still transitioning to pitching. In 62 innings, he posted a 1.26 WHIP and only had 6.4 strikeouts per nine. There were positive signs but still plenty of areas for improvement.

San Francisco envisioned Nathan as a starter and he spent the entire 1998 season in that role. His time at High-A saw him compile a 3.32 ERA with 1.21 WHIP. He had a 118 to 48 strikeout to walk ratio over 122 innings. After being promoted to Double-A, he struggled in four starts. He allowed 15 runs in 15.1 innings with 10 strikeouts and nine walks. He was almost a year and a half younger than the competition in the Texas League so the Giants still viewed him as a strong prospect.

During the next season, Nathan spent more time at the big league level than in the minor leagues. At Double-A and Triple-A, he posted 4.32 ERA and struggled with a 1.39 WHIP. His MLB time wasn't much better as he allowed 42 runs in 90.1 innings (4.18 ERA). In 14 of his 19 appearances, he was used as a starter but he did finish two games and earn his first big league save.

Broken Prospect

There was still hope for Nathan's prospect status as the calendar turned to 2000. However, he would become a broken prospect over the next handful of seasons. By the end of 2001, he was a 26-year old coming off shoulder surgery with a 7.29 ERA between Double-A and Triple-A. During this time he walked 70 and struck out just 54 in 108 innings. There were plenty of red flags surrounding him.

These red flags wouldn't go away in 2002. Nathan was a year older at age-27 and he was a year removed from major shoulder surgery. He got hit around for a 5.60 ERA while walking 74 and striking out 117 in 146 innings. For his final two seasons at Triple-A, he was not a good pitcher and he was already in his late 20's. As a scout, this would not exactly scream that this was the type of pitcher a team should go after.

Diamond In The Rough

Luckily, the Twins saw something in Nathan that the Giants might have missed. During his last season in San Francisco, he played the entire year at the big league level, making 78 appearances out of the bullpen. He posted an ERA under 3.00 for the first time at any level since 1997. This was enough for Minnesota to consider him a potential closer and get him included in the trade for AJ Pierzynski.

Bullpen pitchers can take a lot of routes to becoming effective big league players. Nathan's minor league journey was full of ups and downs before he transformed into one of the best relievers in baseball history.