In addition, outfielder Randy Winn asked for his unconditional release and the Orioles complied.
The 36-year-old Hendrickson was signed Jan. 31 as a minor-league free agent. He spent the past two seasons pitching in relief with the Orioles and lifetime is 57-74 with a 5.02 ERA.
Hendrickson had a 3.86 ERA in six appearances this spring. He has been invited to pitch for Baltimore's Triple-A club, but Showalter said the pitcher would weigh his options before making a decision.
"It was tough. He's been in the big leagues for eight-plus years," manager Buck Showalter said. "He's a father, a husband, a solid human being. A professional. But I think he will pitch in the big leagues this year, hopefully for us."
Like Hendrickson, the 34-year-old Riske can seek a major-league job elsewhere. Riske left camp over the weekend to attend to a family matter in Las Vegas, according to Showalter.
Riske is 20-20 lifetime over 11 seasons with Cleveland, Boston, the Chicago White Sox, Kansas City and Milwaukee.
VandenHurk was acquired in a trade with the Florida Marlins last July. He began his stint with the Orioles in the minor leagues before being called up by Baltimore on Aug. 16. He went 0-1 with a 5.09 ERA in nine games with the Orioles and is 8-10 with a 5.86 ERA in 42 career appearances.
The moves leave Mike Gonzalez as the only left-hander in the Baltimore bullpen. The final makeup of the bullpen will depend on how Brad Bergesen bounces back after a line drive bruised his forearm Friday.
Bergesen threw on the side Monday and reported no discomfort, according to Showalter. He is scheduled to pitch in a minor league game Wednesday.
Felix Pie beat out Reimold as an extra outfielder, even though Reimold batted .315 with three homers and 10 RBI. Pie, who took a .254 batting average into Monday's exhibition game against Detroit, is out of options. Therefore, the Orioles would risk losing him by dropping him from the 25-man roster.