With the official entry list for the 2013 World Superbike Championship still to be announced, it is rumoured that the current confirmed 18-strong grid will be bolstered by at least two more riders before the season gets underway in Australia next month.

As it stands, 18 riders full-time riders are certain to be on the grid at Phillip Island on February 22-24, but a 19th entry is expected to be submitted by experienced WSBK veteran Ivan Clementi, who has been regularly tipped by the Italian media to be returning to international competition after several years racing at domestic level.

Fresh from finishing runner-up to occasional WSBK rider Matteo Baiocco in the CIV Italian Superbike Championship last year, Clementi - who began 116 WSBK races between 2002 and 2006 - is anticipated to be stepping up aboard a privateer BMW S1000RR run by HTM Racing.

Though it hasn't been officially announced, Clementi's presence in Jerez for WSBK testing this week suggests the 38-year-old is on course to ride in 2013.

Somewhat less certain, however, are reports that Liberty Racing will be on the grid this year, also with a privateer BMW ridden by Lorenzo Lanzi. The race-winning Czech team has been frequently mooted for an entry, though a tumultuous 2012 campaign - which saw it part company with three riders, come into conflict over sponsorship payments and skip rounds altogether - and a lack of recent updates suggested nothing would come of it.

However, German publication Speedweek.de is reporting that Liberty Racing (seemingly without the backing of Effenbert) has gone ahead and purchased a pair of 2012 S1000RRs from BMW Italia with the intention of entering experienced racer Lanzi, who competed with the team during the final three rounds of 2012.

According to the Speedweek, the team is preparing to make its return at the start of the European season, which kicks off in April at Motorland Aragon.

Notably, even with the inclusion of Italian riders Clementi and Lanzi, the WSBK grid is currently an all-European affair, six of which are already from Italy.