MESA, Ariz. -- There are plenty of reasons to believe the A's will be a much-improved ballclub this year.
Their bullpen has been restored, and their offense seemingly employs tough outs top to bottom.
Then there's this: Oakland's rotation has consistently been one of the best in the league. The A's believe this trend will continue with a Sonny Gray-led staff that's brimming with talent in the form of several young arms -- Chris Bassitt, Jesse Hahn and Kendall Graveman -- and a veteran in Rich Hill.
But there are also questions of stamina and durability for this group, and the A's may go only as far as their rotation takes them.
"I think they all have the stuff to really surprise some people this year," catcher Josh Phegley said.
Bassitt, in particular, could emerge as a difference-maker, having rectified a once-overcomplicated delivery by imitating the one used by Gray, his offseason workout partner. After beginning the 2015 season at Triple-A, the 27-year-old Bassitt is now penciled into Oakland's rotation as the No. 3 starter.
"I think Bassitt is going to bonify himself as a top-of-the-rotation starter," catcher Stephen Vogt said. "His stuff is electric, he's smart, he's learning a lot and he's repeating his delivery on a much more consistent basis this year than he did last year.
"For a guy that's all elbows and knees and everything going everywhere, he's staying more compact this year, and I think you're going to see some better results because of it."
"I think Bassitt's got some unbelievable life on his ball," Phegley said. "He's not always spotting up, but he's effectively in the strike zone and keeps hitters off balance."
Hahn boasts similarly big potential, but will he be able to shake injury concerns and return to the starter the A's saw in the first half last year? The right-hander posted a 3.35 ERA in 16 starts before being shut down with a right forearm injury, and there's long been worry surrounding his potential to undergo a second Tommy John surgery.
Graveman, too, was hit with the injury bug last year, but in the form of a left oblique strain, and he's since turned the focus back to his pitching. Because of that, he should prove to be reliable in the fourth spot in the rotation with a strong repertoire that now includes an effective changeup that he can throw to right-handers.
That leaves Hill, whose resurgence in a small sample size with the Red Sox last year -- he posted a 1.55 ERA in 29 innings -- led the A's to give him a one-year, $6 million deal. It's a low-risk, high-reward signing, but Hill's ability to contribute from the No. 2 slot behind Gray will be paramount to a club that's lacking starting depth beyond left-handers Felix Doubront and top pitching prospect Sean Manaea.
Last year, the A's utilized 13 starters, the most since they needed 14 in 2009.
"We're really comfortable with the guys we have," A's manager Bob Melvin said.
"We have six quality starting options right now, and then Manaea is No. 7," Vogt said. "When he's your seventh option, you feel pretty good about it."
"We have the bullpen additions that are going to be really good for us, and I think we have the right guys to do the job to keep us in the game offensively, so it's going to come down to these guys," Phegley said. "I think we all like what we see."
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, follow her on Twitter @JaneMLB and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.