Forgive Jamie Dixon if Pitt's season flashed before his eyes when Talib Zanna collapsed on the court. A hush fell over Petersen Events Center on Sunday when Zanna twisted his left ankle against Virginia. Pitt already had lost one key contributor when sophomore swingman Durand Johnson suffered a season-ending knee injury Jan. 11. The Panthers can ill afford to lose Zanna, the 6-foot-9 fifth-year senior who switched from power forward to center this season and has had three double-doubles in ACC play. “You talk about losing guys and anybody is going to be concerned,” Dixon said. “No team is deep enough to lose its second- and fourth-leading scorers. There's only so many things you can withstand.” Not only is Zanna Pitt's No. 2 scorer (12.8) and leading rebounder (7.6), but the Panthers also are still trying to replace Johnson's 8.8 points a game. Some of that burden has fallen on the shoulders of fifth-year senior swingman Lamar Patterson, who is trying to carry a greater scoring load. Johnson's presence provided a dangerous 3-point threat who was improving as a defender and rebounder and one whose presence gave the Panthers frontcourt flexibility. When Johnson entered a game, Pitt could sub for Patterson or switch him to shooting guard or power forward, depending on matchups. “It's affected me a lot,” Patterson said. “Durand's a good player, and he was about to become a big force. He was becoming more consistent for us, knocking down shots and doing other things people didn't know Durand can do. Durand's a guy that gets me going. He's the soul and heart of this team. When he went down, it hurt us all. I'm playing more minutes, and we've got to compensate for what he did for the team.” It's a far cry from last season, when Dixon was trying to keep 10 players while splitting their playing time. What's worse, Pitt doesn't have a true backup for Zanna after its past two post recruits left as freshmen. Two years ago, Khem Birch transferred to UNLV. Last year, Steven Adams declared for the NBA Draft. Rutgers transfer Derrick Randall, a 6-9 junior, has averaged three minutes the past two games. Joseph Uchebo, a 6-10 sophomore junior-college transfer, replaced Zanna against Virginia but was yanked within a minute after a defensive breakdown.