When Sonny Gray pitches tonight in Toronto -- if he's not traded before then -- the Nationals and Yankees will be paying close attention.
Sources say the A's and Nats have remained in contact since finalizing the deal that sent relievers Sean Doolittle and Ryan Madson to Washington earlier this month.
The A's are prioritizing young center fielders as potential returns on Gray. They have interest in Estevan Florial, the Yankees' No. 5 prospect and No. 91 overall as ranked by MLBPipeline.com.
As for talks between the A's and Nats, we shouldn't be surprised.
Mike Rizzo took over as general manager of the Nationals in 2009. Since then, the two teams have agreed to 11 trades. That's an average of more than one per year.

So why is it possible Rizzo and A's executive vice president Billy Beane could reach accord on a 12th trade, less than two weeks after their most recent one?
The Nationals' needs may have changed since the Doolittle-Madson deal, with the news that Stephen Strasburg experienced right forearm stiffness during his most recent start. Sources say the Nats are prepared to trade for a starting pitcher if Strasburg's discomfort becomes a long-term issue. The Nationals already are dealing with the absence of right-hander Joe Ross, who is lost for the season after undergoing Tommy John surgery.

In trade discussions involving Gray, the A's are said to be focusing on teams that could build their offer around a young outfielder. The Nationals have two: center fielder Victor Robles, who was recently promoted to Double-A Harrisburg; and right fielder Juan Soto, who is on the disabled list at Class A. Robles, 20, is seen as more valuable than Soto, 18. Robles is the No. 5 prospect in all of baseball, according to MLBPipeline.com.
A top Oakland official scouted the Yanks' Double-A affiliate on Monday night, though Florial is playing for Class A Charleston.
The Astros, Cubs and Brewers all have shown interest in Gray, who has a 1.62 ERA over his past five starts.
Trade ticker
• While it's unclear when -- or if -- Rangers ace Yu Darvish truly will become available, Texas officials are preparing for the possibility. One Rangers scout was in attendance at a recent game involving Yankees prospects, further evidence of talks between the teams.
• The Cubs had a scout at Comerica Park on Monday, according to MLB.com's Jason Beck, as Justin Verlander allowed three or fewer earned runs for the 10th time in his past 11 starts. Afterward, Verlander acknowledged to reporters that he thought briefly about how the start against Kansas City could have been his last in a Tigers uniform.

Of course, Verlander controls that to some extent: He has a full no-trade clause. He also harbors the strong desire to pitch for a contender. Having thrown two no-hitters and having won an American League Most Valuable Player Award and an AL Cy Young Award, pursuing an elusive World Series title is foremost in Verlander's mind.
The Tigers and Cubs remained in ongoing trade talks on Monday, sources said, and the Cubs are one team to which Verlander likely would approve a trade. The Cubs also have interest in Detroit catcher Alex Avila.
• Despite an apparent long-term trade fit, the Mariners aren't speaking with the Giants about first baseman Brandon Belt, sources say. Instead, Seattle is focused on starting pitchers.
• The Indians pursued J.D. Martinez before the Tigers dealt him to the D-backs, and they're still looking to add a veteran bat. Mets infielder Asdrubal Cabrera -- who spent most of his Major League career in Cleveland -- is one possibility the Tribe is actively considering, one source confirmed a report by ESPN's Jerry Crasnick.