This is a list of major leaguers who played a game, or even more in Great Britain. Some were just single game appearances, and some were tours of the country. People forget that from the late-1880's, until just before World War II, that major leaguers used to tour Europe in the off-season on a regular basis.
This would have been a pretty good team, particularly in the outfield and with the starting pitching.
I would take any of these guys over what the Royals are putting out there every day.
Read up on Roland Gladu and John Foster. They were pretty good ball players, even if you never heard of them.
Catcher — Jerry Grote, New York Mets
First base — Willie Stargell, Pittsburgh Pirates
Second base — Quilvio Veras, San Diego Padres
Shortstop — George Wright, Boston Red Stockings
Third base – Roland Gladu, Boston Braves
Outfielder — Cap Anson, Chicago White Stockings
Outfielder — Tris Speaker, Boston Red Sox
Outfielder — Sam ―Wahoo Crawford, Detroit Tigers
Utility — Jim Thorpe, New York Giants
Starter — Bob Feller, Cleveland Indians
Starter — AG Spalding, Boston Red Stockings
Pitcher — Urban Faber, Chicago White Sox
Reliever — Tug McGraw, Philadelphia Phillies
Reliever — John Foster, Atlanta Braves
Manager — John McGraw, New York Giants
Coach — Hughie Jennings, Detroit Tigers
Umpire — Augie Donatelli
Outfielder — Billy Williams, Chicago Cubs
Outfielder — Sammy Sosa, Chicago Cubs
Starter — Christy Mathewson, New York Giants
You can see more of their individual achievements in Great Britain here at the great site Baseball GB.
I think I would actually switch Cap Anson to 1B, and put Pops in LF. People forget, he started out as a decent outfielder.