The Germany international welcomes the arrival of the Spaniard at Bayern Munich and insists it is inevitable some "very, very good players" will miss out on a starting spot
The 22-year-old completed a €20 million switch to Sabener Strasse on Sunday after the European champions successfully beat Manchester United to the midfielder's signature.
Thiago's arrival will add further competition to an already talent-laden midfield at the Allianz Arena for the coming season, but his new team-mate Kroos insists it is up to the coach to select the best starting XI possible.
"It's Pep's job to assign Thiago to a position," the 23-year-old told Tageszeitung.
"I think he's a very good footballer, and good footballers are always welcome.
"In a team which has so much quality, a few very, very good players will have to sit on the bench, just like last season."
The Bavarian giants will face Borussia Dortmund in the Supercup on July 27.