On Wednesday, it was announced that free agent right-hander Taijuan Walker would re-join the team for whom he made his major-league debut with, the Seattle Mariners. The contract is an affordable one-year deal worth $2 million guaranteed. Walker can make $1 million in additional incentives.
The 27-year-old right-handed pitcher had been non-tendered by the Arizona Diamondbacks after missing the better part of the last two seasons due to Tommy John surgery and a bad shoulder strain. While his health is an obvious question mark, he was healthy enough to pitch in a major-league game last season and by all accounts has had a regular offseason, making him a strong candidate to have somewhat of a comeback campaign. While it should be noted that he lost about one mph on his fastball from 2018 to 2019, that could’ve simply been the result of some lingering effects from the shoulder strain.
The Mariners are a good landing spot for Walker, as their rotation is rather unproven. Beyond left-handed pitcher Marco Gonzales, the Mariners rotation features some considerable upside but with very high risk. Walker joins a rotation mix including Yusei Kikuchi, Justin Dunn, Kendall Graveman, Nick Margevicius, Nestor Cortes Jr., Erik Swanson, and Justus Sheffield.
Kikuchi struggled mightily in his first season in the majors but has been providing promising returns in the early portion of spring training. Margevicius and Cortes saw significant time in the major leagues last season, as Margevicius pitched 57 innings, chiefly as a starter, for the San Diego Padres, struggling to the tune of a 6.79 ERA, while Cortes spent some time coming out of the New York Yankees bullpen, pitching 66.2 innings of 5.67 ERA ball.
Margevicius’ struggles weren’t unexpected, as the Padres promoted him to the major leagues in 2019 less than two weeks after his first assignment to Double-A. The lefty will be 24 years old this season and stands a chance of developing into a strong number four starter with the most likely outcome of a five. Cortes seems more like a lefty long reliever.
Dunn, Swanson, and Sheffield are among the Mariners’ most promising young pieces, but they’ve each endured their fair share of growing pains, as they’ve transitioned to the majors. While these pitchers have the potential to break out in a big way for the Mariners, there are no guarantees.
Sheffield is my favorite of the three, as his numbers were impacted by a pair of bad starts against the Yankees and Chicago White Sox, respectively. Outside of these poor performances, Sheffield posted a 3.62 ERA last season. I believe that he runs with one of the spots in the Mariners rotation based on his wide selection of above average to plus pitches and strong control. He looks like a potential ace.
While Dunn put up a 2.70 ERA over 6.2 innings at the end of the season, it came with a 5.76 FIP and a 9:5 BB:K ratio. He walked 12.2 batters per nine innings compared to just 6.8 strikeouts over the same rate. Personally, I would consider the control issues to be a fluke and expect Dunn to get more comfortable in the major leagues over time. The upcoming season seems likely to be somewhat of an adjustment year for Dunn, but by the time Opening Day 2022 comes along, he has a very realistic chance to be a number two or three.
Swanson posted an ugly 5.74 ERA with a 5.96 FIP over 58 innings, split between the bullpen and rotation. While Swanson’s control was superb (1.9 BB/9), he allowed a considerable amount of fly balls, and with that came a very inflated HR/FB ratio (23 percent). While I expect that number to come down a bit, Swanson needs to work on inducing more weak contact, as he allowed 55.9 percent medium contact and 33.5 percent hard contact. This will be the difference between whether he winds up as a control-oriented number three or a long reliever.
My prediction for Swanson is that he winds up in the bullpen based on the lack of a dominant secondary pitch, where I believe that his fastball would play up in shorter stints. He could be the type of reliever who can convert multi-inning saves.
Graveman is a complete unknown. After serving as the Oakland Athletics ace for a few seasons, he saw a swift fall from grace in 2018, as he went from the Opening Day starter to out of the organization in eight months. He missed the 2019 season due to Tommy John surgery but is expected to be good to go for 2020. I would consider him to be a favorite to begin the 2020 season in the rotation, but I could see one of the prospects replacing him throughout the season.
In December 2018, I wrote a piece exploring the possibility of Graveman transitioning to the bullpen. He performed considerably better the first time through the batting order and saw more success in high-leverage situations. With his wide arsenal of pitches, and those two variables, he could be an elite late-inning reliever.
I expect the Mariners to go into the 2020 season with Margevicius serving as the first pitcher up in the event of an injury, seeing as how they may not be inclined to rush Dunn, thought, I expect him to become a rotation staple midseason.
As for the rebuilding efforts, Taijuan Walker makes the most sense as a trade candidate, seeing as how he’s owed $2 million guaranteed with a maximum of $3 million and the ceiling for him is a front-of-the-rotation starter in his prime. My projections have Walker pitching roughly 120 innings of 4.06 ERA ball. On his contract, that performance would probably be enough for the Mariners to acquire a reasonably strong prospect at the Major League Baseball trade deadline.