With the non-waiver trade deadline less than six weeks away, the cavalcade of scouting stars is under way.

Tuesday night in Houston, sources say representatives for the Yankees, Giants, Dodgers, Red Sox and Blue Jays were in attendance as left-hander Wandy Rodriguez allowed two earned runs over seven innings in a 2-0 loss to the Kansas City Royals.

The Astros will listen to offers for Rodriguez, sources say. Interested clubs are aware Rodriguez could have two years and $26 million left on his contract beyond this year, if he reaches the performance bonuses necessary to trigger the club option for 2014. Rodriguez, 6-5 with a 3.29 ERA this season, has made 30 or more starts in each of the past three years.

The Yankees don’t have an immediate need for starting pitching. In fact, their 2.17 ERA in June is the best in the majors this month. But as is the case with many teams, they are one significant injury away from plunging headlong into the market for rotation help. It’s worth noting that the Yankees had interest in acquiring Rodriguez at the trade deadline last year.

Meanwhile, the Giants and Blue Jays have more acute pitching needs. San Francisco could be preparing contingencies in case Tim Lincecum continues to struggle; the Giants don’t have elite starting pitching at the top levels of their farm system. Toronto, meanwhile, lost three-fifths of its starting rotation to injuries last week and has spoken with the Astros about Rodriguez in the past.

The Dodgers are involved in the starting pitching market, with veteran left-hander Ted Lilly still on the disabled list. The Red Sox likely will gauge the health of ace Josh Beckett and performance of fill-in starter Franklin Morales before deciding whether to acquire rotation help.

— Jon Paul Morosi and Ken Rosenthal