With 47 goals from 22 games Roma lead Juventus for the best attack in Italy's Serie A.
However Roma has conceded 38 goals, to the 15 conceded by leader Juventus, prompting the club's sporting director Walter Sabatini to question the Czech veteran's methods.
Roma has also failed to win in its last four games.
"Zeman's work is satisfactory in some respects, but it's clear there are some less positive aspects as well," Sabatini said.
"It's time to ask ourselves whether we need to make a change."
Zeman is a legendary figure in football, having coached a number of top teams, including Lazio, Fenerbahce, Napoli and Red Star Belgrade.
However he is perhaps best known for leading little-known Foggia to Serie A, where it regularly punched above its weight playing an attack-minded 4-3-3 formation, which Zeman still favours.
Zeman led Pescara to Serie A promotion last season and in June 2012 he joined Roma - 13 years after his first spell at the club - on a two-year contract.
Sabatini congratulated the 65-year-old Czech for helping "discover and develop emerging players", but he gave a strong hint that his time could soon be up.
"I don't regret him coming here because he has helped to discover and develop younger players but we have to build on other aspects as well," Sabatini said.
"The current situation is not satisfactory and we need to stop and reflect on whether we missed something as regards the composition of the coaching team."