This is also why projection systems are going to understate how incredibly good the Cubs' position players are. Outside of catcher and probably CF, the first 500 bench PAs due to rest/injury are going straight to Baez(a 3 win player), thanks to the flexibility of Baez, Zobrist, and Bryant. Montero is a super high quality backup C too. Compare to, say, the Dodgers, whose bench consists of 'well I guess if he has a good year he could be part of a platoon' guys, and whose starting 8 has more injury/performance concerns anyway. Also, in theory, you get a higher level/top line version of a player more often for 500 PAs vs 650 PAs if that player is "fresher." Yep, helps to prevent some injuries too. The Cubs insane youth is a big part of this as well, but Zobrist isn't getting even the 15 games off he got last year on a lot of teams.