Per baseball prospectus glossary:
Wins Above Replacement Player, level 1. The number of wins this player contributed, above what a replacement level hitter, fielder, and pitcher would have done, with adjustments only for within the season. It should be noted that a team which is at replacement level in all three of batting, pitching, and fielding will be an extraordinarily bad team, on the order of 20-25 wins in a 162-game season.
WARP is also listed on a player's PECOTA card.
Basically WARP takes pitching, hitting, defense and baserunning into account. The "Wins above replacement" are a counting stat, not a rate state, so of course playing time matters. BUT...if you get a lot of playing time and you suck too much, it's obviously going to work against you.
If I were to rank who I thought have been the most valuable players on this team year to date, without looking up WARP, I really think I would have come up with the same exact order of the top 5.