Jankowski demonstrated solid top-of-the-order potential (.332 on-base percentage, 30 steals) during his first extended big league trial in 2016, but he will have no time to rest on his laurels. The speedster faces an immediate challenge from highly touted prospect Margot, who is considered by many to be the Padres' long-term leadoff hitter and center fielder. Not only is Margot regarded as a defensive whiz, but he also recorded a .351 on-base percentage with 30 stolen bases for Triple-A El Paso last season.
Zinkie's prediction: Jankowski earns the job and Margot opens the season in Triple-A, but Margot becomes the starter in center field or left field by the beginning of July.
After posting an impressive .315/.359/.500 slash line across 237 plate appearances in his debut season, Dahl may be the favorite to open 2017 as Colorado's left fielder. But the youngster benefited from an unsustainable .404 BABIP last year, suggesting he will face some regression without trimming his 24.9 percent strikeout rate. Dahl will be challenged by the veteran Parra, who struggled (.671 OPS) in the first season of a three-year contract with the Rockies after posting a solid .780 OPS in '15.
Zinkie's prediction: Dahl secures the full-time role, with Parra struggling to exceed 250 at-bats as a reserve player.
Expected to be the Padres' regular second baseman, Spangenberg instead was limited to 14 games in a 2016 season that was derailed by a left quad injury. Spangenberg may have trouble reclaiming his job from Schimpf, who overcame a 31.8 percent strikeout rate to produce 20 home runs and an .869 OPS across 330 plate appearances in his debut season. After posting the highest fly-ball rate in baseball by a wide margin at 64.9 percent (minimum 300 PAs) and tying for 52nd in average fly-ball distance -- 328 feet, per Statcast™ (minimum 50 fly balls) -- Schimpf could be set up for continued success in the power department. Meanwhile, Asuaje is hoping to leapfrog both Spangenberg and Schimpf after hitting .321 in Triple-A a year ago.
Zinkie's prediction: Schimpf holds off his challengers and hits more than 30 homers. Meanwhile, Spangenberg falls short of 300 at-bats as a utility man, and Asuaje splits his season between the Minors and the Majors. Neither of the latter two players is likely to impact mixed leagues this year.
Pomeranz endured an inconsistent 2016 season, dazzling across 17 starts with the Padres (2.47 ERA) before producing a 4.59 ERA over 14 appearances (13 starts) with the Red Sox. Now recovered from the elbow woes that hampered him late last year, Pomeranz will hope to beat out Rodriguez for Boston's final rotation spot. The latter dealt with problems of his own in '16, missing the start of the season with a knee injury, and recording an 8.59 ERA before the All-Star break. But the southpaw turned in a terrific second half, registering a 3.24 ERA.
Zinkie's prediction: Pomeranz opens the season in the rotation, with Rodriguez biding his time in Triple-A. Rodriguez makes 15 starts with Boston and has stretches of mixed-league relevance.
Andriese possesses stellar control (lifetime 2.0 BB/9 rate), but he has recorded a lifetime 4.49 ERA as a starter while showing mediocre strikeout skills (7.2 K/9 rate) and struggling with homers (1.2 HR/9 rate). Andriese will enter Spring Training with his sights set on holding off the 24-year-old De Leon, who ranks among the top fantasy prospects for 2017 after posting outstanding numbers (2.61 ERA, 0.94 WHIP, 11.6 K/9 rate) in Triple-A last season.
Zinkie's prediction: Andriese opens the season in the rotation, but De Leon ultimately makes at least 20 starts.
Wacha entered 2016 as an integral part of St. Louis' rotation, having logged a 3.23 ERA across his first 58 career starts. But he went on the disabled list with a shoulder injury for the second time in three seasons and finished the year with a personal-high 5.09 ERA. If he cannot fend off the talented youngster Reyes (lifetime 3.50 ERA, 12.1 K/9 rate in the Minors), Wacha will likely open the campaign in the Cardinals' bullpen.
Zinkie's prediction: Wacha earns the final spot, with Reyes beginning the year in Triple-A. Reyes returns by June and is active in all leagues during the second half.
Glasnow has enjoyed a spectacular Minor League career, using his stellar strikeout skills (career 11.6 K/9 rate) to post an impressive 2.03 ERA in the face of inconsistent control (lifetime 4.4 BB/9 rate). Looking ahead to Spring Training, Glasnow will need to prove that he can throw enough strikes to become a trusted member of the Bucs' Opening Day rotation. The owner of a lifetime 4.93 ERA as a big leaguer, Hutchison will also attempt to convince the Pirates of his viability as a starter.
Zinkie's prediction: Glasnow wins a rotation spot and makes an impact in all mixed leagues.
After missing all of 2015 while recovering from Tommy John surgery, Wheeler was expected to reclaim a rotation spot upon his return last season. However, the right-hander experienced complications in his rehab and did not make an appearance with the Mets. Once considered to be a potential ace, Wheeler will now attempt to defeat Gsellman and Lugo for the final spot in the rotation. The latter two hurlers rescued the team's postseason push by capably filling spots in an injury-riddled rotation last year, with each posting a sub-3.00 ERA.
Zinkie's prediction: Gsellman earns the last rotation spot, with Lugo and Wheeler heading to the bullpen.
Although he has recorded 324 saves and a 2.97 ERA during his big league tenure, Street will need to reclaim the closer's role after producing a 6.45 ERA across 22 1/3 innings during an injury-shortened 2016 season. Street's main challenger is Bedrosian (1.12 ERA, 1.09 WHIP in '16), who was on the verge of taking over the ninth-inning gig when he landed on the disabled list last August with a blood clot in his right arm.
Zinkie's prediction: Bedrosian anchors the bullpen and becomes a fixture in mixed-league lineups.
Likely to field one of the best teams in the National League, the Nationals should provide a wealth of save opportunities in 2017. Kelley may be the favorite to receive most of them, having produced a 2.64 ERA with a 0.90 WHIP and a 12.4 K/9 rate during his initial season with the team. But Kelley has dealt with his share of homer problems in his career (lifetime 1.2 HR/9 rate), which could open the door for Treinen -- who recorded a 2.28 ERA, a 65.9 percent ground-ball rate and a 0.7 HR/9 rate in '16 -- to claim the job.
Zinkie's prediction: After sharing save chances with Treinen at the outset of the season, Kelley eventually emerges as the superior option.
Fred Zinkie is the lead fantasy baseball writer for MLB.com. Follow him on Twitter at @FredZinkieMLB. This story was not subject to the approval of Major League Baseball or its clubs.