Back-to-back wins against Lithuania and Malta earlier this month have boosted the Tartan Army's chances of heading to Russia in the summer.
Gordon Strachan's side go into the final round of matches with their destiny in their own hands, knowing that two victories would all but guarantee a play-off spot.
And Ritchie - who has played a key role in Newcastle's strong start to the current Premier League campaign - could feature against Slovakia at Hampden Park on Thursday, 5th October and Slovenia in Ljubljana on Sunday, 8th October.
The Scotland squad for their next two World Cup qualifiers is: Jordan Archer (Millwall), Craig Gordon (Celtic), Allan McGregor (Hull City), Ikechi Anya (Derby County), Christophe Berra (Heart of Midlothian), Grant Hanley (Norwich City), Liam Cooper (Leeds United), Charlie Mulgrew (Blackburn Rovers), Andrew Robertson (Liverpool), Kieran Tierney (Celtic), Steven Whittaker (Hibernian), Stuart Armstrong (Celtic), Barry Bannan (Sheffield Wednesday), Scott Brown (Celtic), Darren Fletcher (Stoke City), Ryan Fraser (Bournemouth), James Forrest (Celtic), James McArthur (Crystal Palace), John McGinn (Hibernian), James Morrison (West Bromwich Albion), Matt Phillips (West Bromwich Albion), Matt Ritchie (Newcastle United), Robert Snodgrass (Aston Villa, on loan from West Ham United), Steven Fletcher (Sheffield Wednesday), Leigh Griffiths (Celtic), Chris Martin (Derby County).
