First base with and without Mauer

A year ago I figured that Joe Mauer would retire at the expiration of his contract after the 2018 season. His 2017 resurgence may change that equation, but he'll be 35, his daughters will be about ready to start school, he'll have collected more than $200 million in salary over the course of his career -- yeah, he might well decide to hang 'em up.

Then what for the Twins at first base? For that matter, who's behind Mauer for 2018?

Mauer played more than 72 percent of the team's innings at first base. Kennys Vargas picked the majority of the rest. But Vargas

• hasn't been very productive as a major league hitter
• is finally out of options
• isn't a lock to remain on the 40-man roster this winter and
• is seriously contemplating playing in Japan or Korea

Byungho Park might be seriously contemplating a return to his native Korea. He slugged a mere .415 in Triple A, and if Park ain't hitting for power, he ain't doing much. His walk to strikeout ratio with Rochester (28 bases on balls, 130 strikeouts) was ugly. He has one more year on his Twins contract, he's not on the 40-man roster and this front office has no investment in him.

In my opinion, it's likely that neither Vargas nor Park is with the Twins next year.

Many assume that Miguel Sano is destined for first base once that position is vacated (he played 65 inning there this year). My guess is that if he's too big to stay healthy at third base, he's not real likely to stay healthy at first either. The Twins have long ought to avoid a full-time DH, but that is, in my view, his more likely destination if third base doesn't work for him.

Sano is right-right -- bats right, throws right. John Manuel, for this week still the editor of Baseball America and after that a member of the Twins pro scouting department, had a recent piece about the scouting bias against right-right first basemen. (Byungho Park certainly isn't a data point to discredit the bias.)

The hitter in the system who most interests me as a post-Mauer first base candidate is also right-right: Brent Rooker, who raked at two levels in the farm system after the Twins plucked him with a supplemental pick between the first and second rounds.

He's right-right, he's probably not athletic enough for the outfield and as a college senior draft he was older than his competition at both Rookie and High A ball. These are significant drawbacks. He also hit 11 homers in 40 games in the Florida State League with Hammond Stadium as his home park, and that doesn't happen very often.

Presumably Rooker will advance to Double-A in the spring. Then we might get a better read on his future.