Two players are ascending the team's depth chart, and two others are having trouble staying afloat.
As the St. Louis Cardinals traveled north from Florida at the end of Spring Training, they had 26 players in tow and a decent grasp of how their depth chart would be constructed. Much of that depth chart is solidified: The obvious pillars on the infield corners remain intact and productive in the form of Paul Goldschmidt and Nolan Arenado, and while Willson Contreras hasn't produced the way Cardinals fans have hoped, he still has a stranglehold on the starting catcher position.
Brendan Donovan hasn't been quite as productive lately as some might have expected; the power that he displayed in Spring Training and early in the season has diminished, and he is chasing pitches more, but he has shown promise in the past few games and was on fire at the beginning of the season.
While the infielders haven't changed much in the depth chart other than Nolan Gorman earning a larger portion of playing time than some fans might have expected thanks to a sizzling start, the outfield is less settled with the return of Lars Nootbaar, and it was expected before the season that there would be competition for the three spots.
Although the bullpen doesn't have an actual depth chart, roles do change based on pitchers' performances. If someone is routinely lights-out when he pitches, it would behoove a manager to thrust that pitcher into a higher-leverage role. On the flip side, a struggling hurler will often be relegated to a lower-leverage or mop-up role.
Depth charts are merely a blueprint to begin the season, and the Cardinals are already seeing some movement on theirs.