Kello, 30, has spent this week training at the club's Compton facility as manager Dean Saunders runs the rule over the stopper, who is a free agent.
The Czech Republic-born goalkeeper, who has represented Slovakia at international level, spent four successful years with Hearts between 2008 and 2012.
He departed the Scottish club in April 2012 amid heavy interest from several top-flight suitors including Aston Villa, before he undertook trial periods with Ipswich and then Wolves last summer when former boss Stale Solbakken was in charge, although nothing materialised.
Relegation-threatened Wolves are on the lookout for reinforcements with first-choice Carl Ikeme facing the remainder of the season on the sidelines having broken his hand punching a dressing room tactics board at the interval against Bristol City last time out.
With Wayne Hennessey (knee) already sidelined, Dorus De Vries is set to take the number one shirt while Aaron McCarey has already been recalled from his loan spell at Walsall as back up.