Having taken Thomas Gravesen, Jiri Jarosik and Derek Riordan to America, plenty of thought will surely be given over to whether the trio who arrived last summer can contribute in the coming campaign or should move on.

Riordan could have thrown himself a lifeline with his fine equalising goal against Chicago Fire, a left-footed volley with the outside of his boot which from 20 yards flew into the far right corner.

However Norwich reportedly remain keen on the 24-year-old Hibernian frontman, who was a fringe member of the squad last season and looks likely to be involved even less often in the new campaign.

It could be the Canaries who benefit from the clinical finishing of Riordan which received generous praise from Hoops team-mate Paul Hartley after the 1-1 draw with Chicago.

Former Real Madrid midfielder Gravesen, 31, has been given several chances to stake his claim for a regular place but moved no closer during the American trip to showing he deserves selection on merit, while 29-year-old Jarosik has only in fits and starts showed the quality which once earned him a move to Chelsea.

There will be limited time to shake off the effects of the eight-hour flight home and six-hour time difference, given Celtic are back in action on Thursday night when Gordon Strachan's side tackle Newcastle in a friendly at St James' Park.

Strachan was impressed by the Major League Soccer All-Stars who overwhelmed his side in Commercial City last week, winning 2-0, but Sam Allardyce's Magpies side will still be a step up in class of opposition.

The Hoops boss will on the one hand be aware that poor friendly results are not damaging, even if they are not welcomed; Celtic came back from worse last summer when they lost 4-0 to DC United.

But on the other hand there are less than two weeks to go before Celtic begin the defence of their Clydesdale Bank Premier League title with a home match against Kilmarnock on August 5.

Against Newcastle he will be seeking a much improved display, with Celtic facing four league matches and two Champions League qualifying games in a busy August.

Artur Boruc looks to have lost none of his sharpness, however the Polish goalkeeper claimed the same could not be said for his team-mates in the Chicago match.

Boruc said in the Evening Times: "The first 45 minutes were really, really embarrassing to be honest. That was because we were poor. Our performance was really bad.

"We managed to get a draw, but we can't be happy with the result."

Strachan is also due to give a verdict on the future of Italian trialist Andrea Capone.

The 26-year-old former Cagliari midfielder, who is a free agent, played the first half against Chicago before compatriot Massimo Donati took his place.

Capone has now played a part in three friendly matches, scoring in the 5-1 win against QPR, and will be eager to know whether Celtic plan to offer him terms.