Barry Bonds' obstruction-of-justice conviction, for giving an evasive answer during grand jury testimony about steroids in sports, appeared to be on shaky ground Thursday as several federal appeals court judges questioned the evidence of his guilt and suggested he had been blind-sided by the charge. A jury deadlocked in 2011 on three charges that Bonds committed perjury by denying in 2003 grand jury testimony that he had ever knowingly used performance-enhancing drugs.