Just two weeks ago, Atlanta United had a panoply of options in central defense.

It was so good that Michael Parkhurst, one of the league's best-ever central defenders and club captain, couldn't get a game even when the Five Stripes shifted to three center backs.

Perhaps, then, the 35-year-old had just finally lost a step?

In Round One of the Audi 2019 MLS Cup Playoffs, Parkhurst showed that he could certainly still ball. It was just that Miles Robinson played at a Best XI level this season, earning his first cap with the US men's national team and forcing Parkhurst to the bench. Franco Escobar and Leandro Gonzalez Pirez were still two of the league's best and better suited to flanking Robinson in a back three than Parkhurst. Florentin Pogba was an overqualified backup.

Funny what two weeks can do. Robinson picked up a hamstring injury with the USMNT and Parkhurst dislocated his shoulder in the dying moments of Atlanta's 1-0 Round One win over the New England Revolution, where he was arguably Man of the Match. All of a sudden, Atlanta's depth in central defense is gone.

Here are the two stylistic options Frank de Boer has in front of him for the conference semifinals against the Philadelphia Union on Thursday (8 pm ET | ESPN2 in US; TVAS, TSN in Canada).

Keep the back three