The Bayern Munich boss was asked about events at his old club involving Rosell and Neymar's controversial transfer.
"No comment," was all Guardiola offered after victory at Borussia Monchengladbach.
Asked about Barca's expected deal for Gladbach goalkeeper Marc-Andre ter Stegen, Guardiola was more forthcoming.
"If Barca have signed Ter Stegen, they've made a very good signing," he said.
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