But how could he not be? Doolittle will enter Sunday's first official workout fully healthy, after missing the majority of the 2015 season with shoulder issues. He's also got a new pitch in his pocket and brother Ryan by his side in big league camp for the first time.
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The right-handed Ryan Doolittle, who excelled out of Double-A Midland's bullpen last season to earn a non-roster invite, has thrown a split-changeup for years, and Sean, who relies heavily on his fastball, is attempting to duplicate it.
"The grip is supposed to do most of the work," Sean said. "There's no spin, there's no hand action involved, it's just grip it and rip it. I've been very encouraged early on by how it's gone, so I'm excited to continue to work on it and see how it plays against hitters."
Sean worked on it some last season during side sessions and revealed it during his final appearance of the season, throwing it four times against Seattle.
"It's on tape," he said. "There's proof."
Sean noted he's also still working on his slider, which he'll start throwing off the mound Sunday.
Adventures in babysitting
A's catcher Stephen Vogt, who is three weeks removed from right elbow surgery, will be limited in activity in the early portion of camp but is already taking dry swings and planning to hit off a tee soon. He's also been catching bullpen sessions all week, utilizing a "quarterback" to throw the ball back to the pitcher, he said.
The plan is for Vogt, who already has full range of motion in his elbow, to start playing in games the second week of March and be ready for Opening Day to catch presumed starter Sonny Gray. Already, he's provided a big assist to his battery mate, offering to babysit Gray's 1-year-old son, Gunnar, on Valentine's Day.
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"I was telling Vogt, 'He's crazy. This kid's crazy, but in a good way,'" Gray said. "Vogt was like, 'No, I got it.' We were gone for probably three hours and we get back and Vogt was worn out."
"We had so much fun," Vogt said. "Gunnar is running all over the place, so I chased him all over the house. We were taking batting practice, we were pulling stuff out of drawers, had the Grammys on in the background. You couldn't draw up a better night for Gunnar and I to hang out.
"If you ever wanna know what Sonny would be like at a year old, watch Gunnar, and if you ever wanna know what Gunnar is gonna be like, watch Sonny. They're twins. Same temperament. Same attitude. We had a blast."
• Newcomer Henderson Alvarez won't appear in any Cactus League games, as he continues rehabbing from 2015 shoulder surgery, but the A's right-hander is so encouraged by his progress -- he's throwing out to 135 feet from flat ground and expects to be off the mound in March -- that he said Saturday he thinks he could be pitching in games by April.
May is likely a more realistic timeline for Alvarez, an All-Star in 2014 for the Marlins who could provide the A's a nice 1-2 punch with Gray in the rotation.
"If you watch him play catch, you'd think there's nothing wrong with him, so it's just about making sure the progression is there and there aren't setbacks," A's manager Bob Melvin said. "That was a great pickup."
• Right-hander Jarrod Parker, who has undergone a second Tommy John procedure and surgery to repair a fractured elbow since last pitching in the big leagues in 2013, has already thrown three bullpens and is expected to be stretched out as a starter this spring.
• Melvin is looking forward to seeing lefty Sean Manaea in action soon and plans to get the club's top pitching prospect -- No. 3 on among the club's Top 30 Prospects-- an early Cactus League start on a split-squad day. He said he could "definitely" see Manaea joining the big league club at some point this season.