Inbox: Who will be in Cards' rotation for '19?

ST. LOUIS -- However you may evaluate the Cardinals' 2018, I think we can all agree it has been an eventful year. From changes in the dugout to the emergence of new faces to the acquisition of a perennial All-Star, there has been intrigue, emotion and debate woven throughout the past 12 months.
Thank you for making Cardinals.com the place you came to digest it all. Your interest and interaction make this job both rewarding and entertaining. Thank you for that.
But as this year nears its end, another sits on the horizon. And in this week's Inbox, let's take a few moments to dig into some questions that will carry over into 2019.
:: Submit a question to the Cardinals Inbox ::
With so many pitching options, does the team have a preliminary idea of who will be in next year's rotation?
-- Adam Mettrick (@amettrick)
Without question, options are plentiful. The Cards could easily come in with a competition of 10 for five rotation spots. Let's start with the givens. Miles Mikolas will be starting, likely on Opening Day. Jack Flaherty, Michael Wacha and Carlos Martínez have been assured spots, as well. Barring injury or a change in roles (e.g. shifting Martinez back to the bullpen), that leaves one spot for Adam Wainwright, John Gant, Austin Gomber, Dakota Hudson, Alex Reyes or Daniel Ponce de Leon to seize.
Wainwright has an edge for the final starting job if he returns healthy, but Spring Training performance will offer clarity to the surplus. The Cardinals plan to use the surplus to improve the bullpen, which could feature several of these arms in key spots.
Do the Cardinals view Tyler O'Neill as an everyday player?
-- Curt H. (@cjheiden6)
They view O'Neill as having the potential to be an everyday player, but he's not going to be given that sort of playing time just yet. As it is, the Cardinals have every intention of letting Dexter Fowler open the season as the starting right fielder. O'Neill will provide backup at all three outfield spots.
O'Neill profiles as an above-average defender, and he certainly has the power potential to make an impact at the big league level. His biggest holdup remains contact rate. O'Neill posted an underwhelming .303 on-base percentage in 61 games with the Cardinals last season, and he struck out in 40 percent of his plate appearances. Those would have to improve for him to warrant 500-plus plate appearances a season.
Will the Cardinals try to sign Miles Mikolas to a long-term contract in the offseason?
-- Stephen S., Tulsa, Okla.
Mikolas seems the ideal candidate for an extension, and I do expect the Cards to explore his interest in engaging in such negotiations. Depending how consumed the Cards are with other more pressing work this offseason, pursuing such a deal may be something the club puts off until Spring Training.
One of the reasons Mikolas signed for only two seasons when he was ready to return from Japan was that he wanted to keep his long-term options open. If he can replicate what he did in in '18, Mikolas will command all sorts of interest on the open market next offseason. But he also seems to be enjoying where he is. The comfort of having Spring Training in his hometown and the rapport he has with pitching coach Mike Maddux are among the factors that may compel Mikolas to forgo free agency and commit to sticking in St. Louis beyond '19.
Signing Mikolas to an extension would also help eliminate some of the Cardinals' future uncertainty, as he is one of three starting pitchers (along with Wacha and Wainwright) who will be free agents at the end of next season.