Saints, seeking an end to a four-match winless run in the Clydesdale Bank Premier League, play Dundee United on Boxing Day before matches with in-form Inverness and bottom club Dundee.
The Perth men are part of a pack chasing a place in the top six ahead of the winter break and a two-week hiatus and may have to negotiate the festive fixtures without Chris Millar.
Midfielder Millar was withdrawn from Saturday's 2-0 loss at Aberdeen with a groin injury and replaced by Paddy Cregg, who could start at Tannadice.
"Chris has tweaked his groin, so we'll have to wait to assess him and see how he is for the busy Christmas period," Lomas said.
"It gives somebody else an opportunity to step in and show their worth."
With Dundee now in the top-flight, the Tayside derby may have less significance for United, but for St Johnstone victory over their near-neighbours would provide a welcome fillip.
Lomas maintains his side can defy their recent run against a United side full of talent.
"Any team can beat anybody on any given day," Lomas said.
"It'll be tough because they're a decent team and they've got decent players, (Johnny) Russell, Jon Daly, (John) Rankin."
- Sports & Recreation
- Clydesdale Bank Premier League
- Dundee United