SCOTTSDALE, Ariz. -- For a pitcher, the road back from Tommy John surgery is a marathon and not a sprint, something that Diamondbacks right-hander Corbin Burnes has been reminded of often over the past nine months or so.
Burnes threw his first short-box bullpen session Friday and his second Monday, and while they are big steps forward, he knows there's still a lot of road ahead of him.
"I've got another one Friday," Burnes said. "And then pretty much two a week for at least a month or so. Just got to stick with the process and build up."
A short-box bullpen is where the catcher sets up on top of the plate instead of behind it. It is designed to remind the pitcher that it's not a max-effort pen.
In his previous session, Burnes said he threw only fastballs. Monday, he mixed in a couple of curveballs, and over the next few weeks he hopes to have all his pitches incorporated.
Burnes has felt good throughout his rehab -- which is, of course, a good thing, but it can also make it more challenging for him to rein his effort level in and not try to do too much too soon.
"It takes a lot [to] not try to fire one off as hard as I can," Burnes said. "Gotta trust it, keep the effort level at 80 to 85 percent, but it's just good to get up the slope again. It's definitely tough to trust the process of the slow build to get back when, historically, once I start throwing bullpens it's three or four then I'm in a game. So it's going to be tough next week, after I throw about the third or fourth one and I'm ready to face hitters."
It will depend on how his rehab continues to progress, but the expected timeline for Burnes' return to the active roster is sometime around the All-Star break. There are some checkpoints before that where he might be able to speed that up a bit, but patience will be required.
Pitchers recover differently from Tommy John surgery, with a number of them saying that it takes a while after they return to feel back to normal.
To try and make sure he is as sharp as he can be when he does return, Burnes has had a singular goal to this point.
"My main focus through all of the catch play, through rehab and throughout the rest of my rehab is all about commanding the baseball," Burnes said. "The time I'm coming back in the season, I need to be able to be at the top of my game. And to do that, I gotta be able to command the baseball. You hear a lot of guys say that it takes a handful of starts for them to know pitch shapes and where it's going. So my goal is once I'm back in a game, it's like I never left off knowing the pitch shapes."
Time change reminder
The Diamondbacks have changed the start time of Friday's game with the Brewers from 1:10 p.m. MST to 6:10 p.m. to combat the expected daytime temperatures, which are expected to be over 100 degrees.
Arizona manager Torey Lovullo said the team will also be mindful of how much work players do in the sun pregame later this week, and he has requested that player development send him some extra catchers, so no one goes more than four innings behind the plate in games.