Tom's statement, "If the Twins intend to be contenders in 2019" is a key point to consider.
The roster that was put together in 2018, with several short-term free agent contracts to veteran players, was an obvious attempt by the front office to bridge a gap while young major leaguers matured, minor leaguers developed, and large contracts came off the books. But I suspect that contention in 2019 was not the goal of that strategy, rather, I think the club was looking at 2018 and 2019 as "competitive" years with 2020 as a contention year.
2018 became a disappointing, non-competitive year when the free agents didn't perform as expected and the young major leaguers lost time due to injury and suspension. Now the best that can be hoped for in 2019 is a development year for the youngsters. That means lots of at bats for an every-day outfield of Rosario, Buxton, and Kepler. Polanco shifting to second base to see how his glove will play there. Sano and Austin splitting time at first base and DH. Any plan that leaves Buxton on the bench until the late innings minimizes his true value as a player, which is helping out the pitchers and his fellow outfielders (and infielders!) by providing platinum glove level fielding for nine innings.
I will also take the opposite side of Tom's argument that there's nothing wrong with putting Sano on the bench if he starts the season slumping. As long as he is physically able, he belongs in the lineup, primarily as a DH. In his first year with the club, he provided plenty of value of the DH spot. I would argue that moving him around the diamond since then has taken away from his focus on hitting.
Grossman and Cave have done all they can to fill in where needed. I've got no complaints about their effort or character. I just don't see either of them as a starting-caliber DH or outfielder on a contending team. And with 25-man roster spots for position players so scarce these days, I don't see how you can keep carrying players with little positional flexibility. Maybe you can carry Cave as a lefty swinging DH/1B/OF for platoon purposes.
I don;'t understand why so many people on this board are down on Cave, particularly as bad as Kepler has been at the plate. The comparison for 2108:
Cave - .269/.318/.481 (.797), 113 OPS+. 1.5 WAR, 13 HRs in one half a season.
Kepler - .224./.319/.448 (.727), OPS+ 96, 2.8 WAR, 20 HRs in a full season.
Cave was the better hitter last year. I say they are about wqwual in the field, good in the corners, passable in center. TO me, it's Kepler who doesn't look like a starting-caliber OF on a contending team. IF, and it's a big if, Cave is what he was last year for a full season he represents a clear upgrade for the TWins at the plate over Kepler. Even Molitor seemed to recognize that last year by hitting Cave 3rd at the end with Kepler 7th. Cave strikes out too much but that will improve if he gets the same 3 year run Kepler has gotten.
Next year Cave should start in RF if Buxton is in CF with Kepler at 1B if Mauer retires. Cave in CF if Buxton can't make it (again), Kepler as 4th OF/part time DH/part time 1b if Mauer stays.