John Rieger-USA TODAY Sports
4. Taijuan Walker – RHP
When the Mariners selected Walker in the supplemental round of the amateur draft in 2010, they knew that they were getting a young kid with an explosive arm. Fortunately, he signed to a contract and began to shoot up through the Mariners system. At the beginning of 2013, MLB.com had Walker listed as their #5 overall prospect. Since his Major League debut on August 30th, Walker has made three starts and even picked up his first big league victory. While he is still only 21 years old, Walker is under Seattle control until at least 2019 and doesn’t even begin to become arbitration eligible until 2016. He provides the firepower in a right arm that the M’s have desperately been lacking behind Felix Hernandez and could create quite the dynamic duo down the line.