Shiells is attending this week's training camp in St Andrews due to injury concerns over three of the four props named in Andy Robinson's 34-man squad last week.
Ryan Grant suffered a head knock in Glasgow Warriors' match at Treviso at the weekend, while Allan Jacobsen (hamstring) and Geoff Cross (concussion) are returning to fitness.
The 23-year-old Shiells, who attended Kelso High School, represented Scotland at under-19 and under-20 level and joined Newcastle in 2009. He has made 49 appearances for the Falcons.
Robinson said: "We've invited Grant to train with us given some of the recent injuries we've had on both sides of the front row."
The Scottish Rugby Union anticipate Jacobsen, Cross and Grant to be fit for the November 11 clash with the All Blacks at Murrayfield, but the propping options are a concern.
Cross is the only specialist tighthead in the squad, while four props are required on a matchday, with two to be named among the replacements.
Kyle Traynor, who left Edinburgh for Bristol in the summer and won three caps as a replacement in 2009, is the only fit prop at present, leading to Shiells promotion.
There are a number of injury concerns elsewhere in the squad, with limited training today for locks Jim Hamilton (ribs), Al Kellock (back) and Richie Gray (ankle), flanker Ross Rennie (shoulder), stand-offs Ruaridh Jackson (shoulder) and Greig Laidlaw (neck), centre Nick De Luca (ankle) and wing/centre Sean Lamont (facial).
Robinson will announce his Scotland captain on Wednesday.
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