IT'S understood that Partick Thistle stopper Marc Twaddle is set to be the subject of a £25,000 bid by St Johnstone.

The 21-year-old is believed to have been the subject of an initial enquiry by McDiarmid Park boss Derek McInnes at the end of last season, which was met with short shrift by the Firhill club.

However, Saints boss McInnes is now without established cover after the summer departure of long-serving veteran left-back Goran Stanic to East Fife.

The Perth chief is understood to have failed in a January bid to land Hearts promising young defender Jason Thompson in January and has become an admirer of Twaddle's in the meetings between the clubs last season.

McInnes is then have believed to switch his affections to Dundee defender Paul Nixon, whom he was desperate to land during the close season, but Nixon's departure to Dundee United has meant that the former Ranger is once more in the hunt for Twaddle.

However, with the player having signed a new one-year extension at Firhill in the spring which nails him to the Jags colours until 2010, it is believed Thistle will rebuff any such bid, with the Firhill valuation of their outstanding defensive talent - who has already cut the mustard at SPL level with Falkirk - thought to be closer to a six figures Twaddle's importance to the Thistle cause has been further amplified by the cruciate ligament injury to skipper Alan Archibald that will keep him out until mid-November at least.

Although Jags boss McCall moved shrewdly this summer to bring in experienced left-sided cover for Archie in the shape of Ian Maxwell, Twaddle is the only other naturally left side orientated Jags defender in the Firhill squad.

It is believed that ex-Rangers kid Twaddle is one of the operators that McCall rates as good enough to perform for Thistle should they one day make it back to the SPL, while the player is known to be fully committed to the Partick cause and only last week reported back for pre-season sharpening sessions some four days early.

McCall is also known to take great pride in the promising young batch of performers he is moulding into a team he believes will be good enough to make Jags bona fide First Division title challengers once again.

So it appears that McInnes' hopes of prizing Twaddle away from Partick appear remote, but St Johnstone are set to head south for a pre-season training camp on Thursday.

The McDiarmid Park gaffer McInnes is believed to be desperate to fill his defensive vacancy before moving his squad to base camp south of the border.

As such it is believed that there is some urgency in the Perth outfit's need to secure Twaddle's signature.

With Thistle having added only Maxwell from St Mirren and Paul Paton from Queen's Park this summer the Firhill faithful will monitor closely the Jags' reaction to any subsequents Saints bid. A firm rebuttle is needed to gird belief in the Firhill board's promotion ambitions.