Lazetic has joined Siena on a season-long loan deal with the option of a further 12 months if he impresses with the top-flight newcomers.
The Serbo-Montenegrin spent last term away from Como as he enjoyed spells with both Chievo Verona and Lazio.
The 25-year-old midfielder becomes the latest addition to the Siena ranks as the minnows prepare for an arduous fight for survival.
Meanwhile, Siena have once more been linked with a swoop for Brescia striker Igli Tare.
Siena are desperate to bolster their firepower and have been mooted as suitors of the likes of Tore Andre Flo and Diego Milito.
Albanian marksman Tare has been a target for Siena since the club secured promotion to Serie A but it had been thought the forward would stay with Brescia.
