The Pittsburgh Pirates were on the back foot again this week, forced to explain the disappearance of fan-funded "Bucco Bricks" and the delay in their return to PNC Park.

The frustration was heightened after fans shared with KDKA-TV in Pittsburgh that some of the bricks, which had been located in front of the home plate entrance to the stadium, were found at a recycling plant in the area.

The team told multiple outlets Tuesday that the bricks were in the process of being returned for a "more permanent display." The bricks had been removed as part of renovations done outside the stadium, and the Pirates missed their goal of having the new display ready for their home opener on April 4.

The "Bucco Bricks" were introduced in 1999, with the team saying it sold about 10,000 of them. A number of the bricks include messages honoring family members, leading to some of the consternation among fans.

"Through the years, a host of environmental factors including weather and foot traffic have led to significant damage leading to multiple, full-scale replacements," Pirates senior vice president of communications and broadcasting Brian Warecki said in a statement. "This cycle of deterioration prompted our organization to look for a better way to preserve these cherished messages over the long term."

The Pirates noted to multiple outlets that the bricks have already been replaced twice since their introduction.

"We respect, appreciate and understand just how meaningful these messages are. We share in that feeling," Warecki said. "We have been actively planning to develop and unveil a more permanent display for these special messages to honor the enduring support that our fans shared then and continue to share in our future. We look forward to sharing those details soon in celebration of our 25th season [in PNC Park]."

The proceeds from the bricks went to the Roberto Clemente Foundation.

The treatment of the legacy of Clemente, one of the most-storied players in franchise history, drew scrutiny over the weekend. The Pirates announced Sunday that they would be adding the No. 21 logo back to the right-field wall at PNC Park to honor Clemente and issued an apology after his family expressed its unhappiness that the sign had been removed for an advertisement.

The Pirates, who haven't played in the postseason since 2015, are already in the cellar of the National League Central after a 4-8 start.