The 2021 Phillies at the moment are playing like the 2015 Mets at the same time of year. The 2021 Mets are either in the role of the 2015 Nats (swept from the top of the division by their rivals for the crown) or the 2015 Marlins (roadkill for the rampaging 2015 Mets after sweeping the Nats). You're also welcome to cite the 1973 Cardinals who had taken first place, lost Bob Gibson to injury and eventually faded.