Seeking to build off an 87-win season in 2014, the Seattle Mariners had reason for optimism entering last season. The off season addition of veteran slugger Nelson Cruz was expected to bolster a lineup filled with talented young players. Things did not go according to plan. Former top draft picks Dustin Ackley and Mike Zunino failed to develop into cornerstone pieces, Hisashi Iwakuma labored through injuries, and Felix Hernandez had his worst season in a decade. The Mariners stumbled to a 76-86 record and a 4th place finish in the American League West.
Seattle has made several changes to their roster in the past year. Only four opening day starters remain in their every day lineup, and the organization has added some veteran arms to provide depth to the pitching staff. Faced with the prospect of surviving in a highly competitive division, Seattle will need to hope for breakthrough performances from some of their young players. Here we will examine a few players who are key to Seattle's hopes for contention in 2016.
Top Candidate: Taijuan Walker. Walker experienced a meteoric rise through the Mariners farm system after being selected 43rd overall in the 2010 draft out of Yucaipa High School in southern California. After shredding the Midwest League in his full season debut in 2011, Walker jumped straight to Jackson in 2012. By the time that season had run its course with Walker competing admirably as a teenager in Double A, he was universally recognized as one of the top pitching prospects in baseball. He split 2013 between Double A and Triple A before making his big league debut in August. A shoulder injury early in 2014 delayed his timetable and he bounced around between Triple A and the Majors before settling in for September with the Mariners.
Walker broke camp with the big club in 2015 and stuck the entire season. He worked 169.2 inconsistent innings over 29 starts. He had eight starts where he allowed five or more runs, and 11 starts where he allowed two or fewer. His filthy four pitch mix including a mid-90s fastball, a plus cutter that works around 90, a solid curve, and an adequate change led to excellent peripherals. His 8.3 K/9, 2.1 BB/9 are both very strong numbers, and his 3.82 xFIP tells a much more optimistic story than his 4.56 ERA.
As he enters his age 23 season, Walker has more upside than any non-royalty in the Mariners rotation. Anticipating even a modest level of progression makes it easy to envision Walker establishing himself as a worthy number two starter. It's still entirely possible that he is a true ace in the long run as well.
Dare to Dream: James Paxton. It feels like Paxton has been around far too long for us to still be longing for him to break through and show his tremendous upside. A 4th round pick out of the University of Kentucky in 2010, Paxton had the chance to move quickly as a college left-hander with power stuff. Injuries and inconsistency have served as roadblocks along the way. Paxton debuted with four strong outings in 2013 before lat and shoulder injuries slowed his progress considerably in 2014. Paxton began 2015 in the Majors before a strained tendon in the middle finger of his pitching hand sidelined him until August. He returned to the Mariners briefly in September, and reportedly made it through the fall healthy as well.
At his best, Paxton's fastball averages 94 and can touch 98. He mixes the heater with a curve and change, both of which are at least average pitches. In 30 Major League starts sprinkled across three seasons, Paxton has thrown 165 innings with 7.4 K/9, 3.6 BB/9, and a 3.70 FIP. In a crowded rotation picture, it's unclear exactly how he fits into the opening day plans for Seattle at this point. As a lefty with power stuff and a solid ground ball profile, Paxton still has a chance to be a difference maker in the big leagues if he can stay healthy. Seattle fans can #daretodream that 2016 is the season their patience pays off.
Rookie Watch: Edwin Diaz. In an increasingly depressing minor league system, Diaz may be the only prospect capable of making a significant impact on the Mariners' fortunes in 2016. With a fastball that works in the mid 90s while touching 98, Diaz has big time heat. His slider has the potential to be a second plus pitch while his change is still behind the other two offerings. After seven dominant starts at High A Bakersfield, Diaz was promoted to Double A Jackson in May. Between the two levels, Diaz finished 2015 with a 3.82 ERA, 9.2 K/9, and 2.9 BB/9 in 141.1 innings.
Diaz likely begins the season outside the Major League roster picture. With a host of other rotation candidates, the Mariners can afford to be patient and allow Diaz to continue his development in the minors, likely at Triple A Tacoma. Diaz has a chance to put himself in position to be an injury replacement as the season progresses. He already shows the ability to miss bats in the rotation, so his arsenal should play nicely out of the bullpen as well. With the option to contribute in both roles, I expect Diaz to make his debut some time in 2016.
Final Notes: The Mariners farm system leaves much to be desired at this point. Their inability to complete the development of solid prospects at the highest level has been disappointing for several seasons now. There is little impact potential anywhere on the farm, and almost nothing of consequence in the upper minors. The Major League roster has enough talent that the team cannot be completely disregarded, but it will require everything to break just right for the Mariners to truly compete this season.