Hollowell was put on waivers Wednesday, Renaud Lavoie of TVA Sports reports.
Hollowell signed a one-year, two-way contract with the Penguins on Monday, per agent Dan Milstein.
Hollowell was placed on waivers Sunday, Chris Johnston of TSN reports.
Hollowell signed a one-year contract with the Rangers on Sunday.
Hollowell was not qualified by Toronto on Friday, Terry Koshan of The Toronto Sun reports.
Hollowell (kneecap) was back in the lineup for AHL Toronto's playoff clash with Utica on Thursday, recording one assist and two shots.
Hollowell, who is with AHL Toronto, underwent surgery for a fractured kneecap and will miss at least 12 weeks.
Hollowell (lower body) was injured in an AHL game and will be out indefinitely, Joshua Kloke of The Athletic Toronto reports.
Hollowell was recalled from AHL Toronto on Tuesday on an emergency basis.
Hollowell was reassigned to AHL Toronto on Friday, per CapFriendly.