Long-time major league relief pitcher Rafael Soriano retired during spring training. He was a fixture in the majors for a decade and had a five-year run as a top-flight closer. A reader requested a Prospect Retrospective for Soriano. His path as a prospect was unusual and worth exploring, so let's examine his career in context.
Soriano was signed by the Seattle Mariners as a free agent from the Dominican Republic in 1996. Originally an outfielder/first baseman, he hit just .167/.250/.204 in 108 at-bats in the Arizona Rookie League in 1998. It was evident that his throwing arm was much better than his bat, so the Mariners moved him to the mound in 1999. The results were immediate: he made 14 starts for Everett in the Northwest League in 1999, posting a 3.11 ERA with an 83/49 K/BB in 75 innings, allowing just 56 hits. His control needed work but his excellent K/IP ratio, low hit rates, and 90+ radar readings pointed to significant upside.
Promoted to Wisconsin in the Low-A Midwest League for 2000, Soriano made 21 starts, throwing 122 innings with a 2.87 ERA and a 90/50 K/BB with 97 hits allowed. League observers were impressed with a fastball up to 93-94 MPH and an improving slider, but noted problems with command and shaky off-speed pitches. He was rated as a high-ceiling Grade C arm in my 2001 book, with the notation that he might be best-off in relief.
Soriano opened '01 with San Bernadino in the High-A California League, making 15 starts with a 2.53 ERA and 98/39 K/BB in 89 innings with a mere 49 hits allowed. Promoted in late July to Double-A San Antonio, he remained effective with a 3.35 ERA and a 53/14 K/BB in 48 innings with just 34 hits. By this point his fastball was up to 95 consistently, his slider was rated as excellent, and he'd shown progress with the change-up. One glitch was a sore shoulder late in the season, but overall this campaign moved him into elite prospect status, earning a Grade B+ in my 2002 book.
After a late start in the spring due to visa issues, Soriano made his big league debut in May, collecting a save in his first game. He then moved into the starting rotation and threw 47.1 innings with a 4.56 ERA and a 32/16 K/BB. He was inconsistent in the majors but this was not unexpected from a young pitcher. A shoulder injury sidelined him in July, then he was sent down to Double-A to finish the season. I gave him a Grade A- entering 2003 and had him rated as the Number Six pitching prospect in baseball.
Soriano was very effective in 2003 as a full-time reliever (1.53 ERA in 53 innings, 68/12 K/BB) and was viewed as a future closer. Alas, he blew out his elbow, needed Tommy John surgery, and did not get back to full strength until 2006. He later got that closer job with the Braves in 2009, then collected 45 saves with the Rays in 2010, leading the league and earning his only All-Star nod. He was the set-up man for Mariano Rivera after signing as a free agent with the Yankees in 2011, then took over as their closer in '12. The 2013 and 2014 seasons were spent closing for the Washington Nationals.
All told, Soriano posted a 2.89 ERA in 636 career innings, collecting 207 saves with an ERA+ of 144. WAR has issues with valuing relievers but his 10.6 career fWAR is respectable and gives him a career valuation in the neighborhood of closers like Brad Lidge (11.6 fWAR in 603 innings, 225 saves), Ugueth Urbina (10.9 fWAR in 697 innings, 237 saves) and Gregg Olson (9.8 fWAR in 672, 217 saves) among closers with a similar number of innings pitched. Soriano ranks 44th on the all-time saves list.
As a prospect, Soriano showed the ability to dominate hitters but had some issues with command, off-speed stuff, and health. He took well to relief work and was an effective pitcher for many years. That's a lot better than being a first baseman who can't hit rookie ball pitching.