The Oakland Athletics' recent acquisitions of Homer Bailey and Jake Diekman may have just been the beginning.

Oakland is reportedly in the market for additional upgrades and pursuing New York Mets right-handers Noah Syndergaard and Zack Wheeler, as well as Detroit Tigers closer Shane Greene, according to Susan Slusser of the San Francisco Chronicle.

"I have not put my phone away," A's general manager David Forst said.

Of the three players the Athletics are chasing, Syndergaard is the most intriguing.

The Mets are "definitely" trading him before the deadline, according to a recent report, but Oakland's competition for Syndergaard's services will be strong. The hard-throwing right-hander is also receiving interest from the Houston Astros, Atlanta Braves, San Diego Padres, and Minnesota Twins.

Syndergaard is struggling through a down year, but he's still striking out nearly nine hitters per nine innings, and his FIP is a respectable 3.64 (14th among qualified starters in the NL). He also isn't eligible for free agency until 2022 and is earning just $6 million this season.

Wheeler may own a 4.71 ERA, but his 3.64 FIP matches Syndergaard, and he's striking out more hitters per nine (9.9).

Wheeler also pitched well in his first start after coming off the injured list on Friday, striking out seven without a walk across 5 1/3 innings. The 29-year-old is scheduled to become a free agent at season's end.

Greene, meanwhile, is producing a career year for the Tigers, authoring the third-lowest ERA (1.22) among qualified relievers, according to FanGraphs, while converting 22 of 25 saves. Opposing batters are hitting just .157 against the 30-year-old, who won't hit the open market until 2021.