This is the fourth piece in a six-part Around the Horn series that is taking a position-by-position look at the Cardinals' projected starters and backup options heading into the 2019 season. After examining the club's catching depth and infield options in recent weeks, let's move onto the outfield.
• Around the Horn:C | Infield corners | Middle infield
Projected starters:Marcell Ozuna (LF), Harrison Bader (CF), Dexter Fowler (RF)
These three outfielders offer intriguing potential, but also plenty of uncertainty. Ozuna is coming off right shoulder surgery that limited his baseball activity this winter. The Cardinals expect him to be a full go by Opening Day, though there is still rehab to complete. Bader brings an elite defensive profile, but also questions about his offensive ceiling. As for Fowler, he may be the biggest unknown of all. The Cards are committed to giving the veteran outfielder another chance as an everyday player, but his leash won't be indefinite.
Other candidates/reserves:José Martínez, Tyler O'Neill, Yairo Muñoz, Drew Robinson, Adolis García
One of the reasons the Cardinals feel comfortable wading into 2019 with questions hovering over their outfield situation is that they tout depth behind those projected starters. The club's decision not to deal Martinez this winter means they'll be bringing back their most consistent offensive performer from the last two seasons. He's an option to back up both Fowler and Ozuna. O'Neill, an above-average defender, can play all three outfield positions. If he can cut down on his strikeouts, he'd also be even more of a formidable presence offensively. Munoz and Robinson aren't likely to play the outfield regularly, but they are capable in a pinch. Garcia will be a ready option at Triple-A Memphis.

Prospect to watch: Dylan Carlson
Carlson isn't as highly ranked on the Cardinals' Top 30 Prospects list as outfielders Randy Arozarena, Justin Williams and Conner Capel, but the 20-year-old will get some exposure in front of the big league staff as a first-time non-roster invitee to Spring Training. The Cards anticipate having Carlson open the season with Double-A Springfield. The switch-hitter has impressed the organization with his plate discipline and low strikeout rate, and there's a hope that getting him into the Texas League will boost his power numbers. It's not unreasonable to project a 2020 arrival in St. Louis.
Biggest lingering question: Can Fowler find his way back?
While there remain concerns about Ozuna's health, there is no bigger wild card than Fowler, who is seeking to rebound from a career-worst year. If he does, the Cardinals will not only deepen their lineup, but they'll have the flexibility to deploy Martinez in optimal spots. If not, the club's depth will be tested. Fowler's .576 OPS last season was the seventh lowest (minimum 90 games) in the Majors. Only two players (Chris Davis and Yadiel Rivera) had a lower batting average than Fowler's .180 mark. This followed a year in which Fowler established career highs in home runs (18) and RBIs (64) in season one of a five-year contract.

Notable number: 20
Though Bader started only 97 games for the Cardinals last season, he quickly distinguished himself among the elite defenders in the game. Bader finished third among outfielders with 20 Outs Above Average, a Statcast™ metric that accounts for the number of plays made and the difficulty of them. What's especially remarkable is that Bader reached that figure despite playing fewer than 1,000 innings.
Statcast™ note
Though the Cards tried to downplay Ozuna's limitations last season, the Statcast™ data was not so forgiving. Ozuna ranked last among the 109 qualifying outfielders with an average velocity of 78 mph on the top 10 percent of his throws. That represented the fourth consecutive season in which the velocity had dipped -- from 91.1 mph in 2015 to 89.4 mph in '16 to 81.8 mph in '17. For comparison sake, Bader averaged 95.3 mph on his max-effort throws last year.