Mike Moustakas, the Royals' two-time All-Star, is part of a crowded group of third basemen on baseball's midseason trade market.

Or is he?

Multiple teams are interested in Moustakas as a first baseman, sources told MLB.com Thursday, and the Yankees are among the clubs that have considered trading for Moustakas and moving him across the diamond.

The Royals expect to deal Moustakas before the July 31 non-waiver Trade Deadline, one source said. The Cardinals and Phillies are among the teams with interest in Moustakas as a third baseman, sources have confirmed via prior reporting by Ken Rosenthal and Jim Salisbury.

The Yankees' overall priority remains acquiring a starting pitcher, but the team also has explored infield upgrades in recent weeks -- even before the injury to American League Rookie of the Year favorite Gleyber Torres .

Without Torres, the right side of the Yankees' infield is likely to feature Neil Walker at second base and Greg Bird at first against right-handed starters. Walker has a .527 OPS this season. Bird's is .725, and the Yankees' overall OPS at first base -- .657 -- ranks 29th among 30 Major League teams.

Moustakas, 29, has played more than 900 games in the Majors but started only twice at first base; both instances came earlier this year. Moustakas has not played since Monday due to back spasms; he has a .784 OPS with 16 home runs in 82 games this season.

Moustakas signed a one-year, $6.5 million deal prior to this season, meaning the Yankees could acquire his entire contract and likely still have room under the $197 million luxury-tax threshold to add J.A. Happ or a similarly priced starter.

As the Yankees remain mindful of keeping their payroll below $197 million, the team could consider creative trades that limit the amount of salary added. For example: If a player's contract is traded and the new team becomes responsible for future payments, the salary paid after the trade no longer counts toward the Yankees' luxury tax payroll calculation. As such, the Yankees could include Walker's one-year, $4 million in a trade offer -- at which point the other team in the transaction likely would insist on a higher-ranked prospect in exchange for assuming the added payroll.

Jon Paul Morosi is a columnist for MLB.com.