SCOTTSDALE, Ariz. (AP) -- The Arizona Diamondbacks begin full-squad workouts with uncertainty at five of the eight non-pitching positions.
That's why new manager Chip Hale uses the word ''competition'' in about every other sentence when talking about the team.
Those who are a lock for the opening-day lineup - barring injury - are first baseman Paul Goldschmidt, center fielder A.J. Pollock and right fielder Mark Trumbo.
The rest could be any number of combinations.
The shortstops are Nick Ahmed, Chris Owings and veteran Cliff Pennington. Owings might play second, though, depending on how Aaron Hill is doing. And the outfield situation depends on whether the Diamondbacks determine that Cuban signee Yasmani Tomas can be converted to a third baseman. If he can, David Peralta, Ender Inciarte and Cody Ross could share time in left field.
If Tomas can't make it at third, that job could go to Jake Lamb. Tomas would go to the outfield with Peralta, Inciarte and Ross candidates to make the squad as backups. Hale said there's even a chance Thomas won't make the opening-day roster.
Then there's catcher, where Hale has said all eight players at that position in camp have a shot at the opening day roster.
Tuffy Gosewisch, who spent nine years in the minors before backing up Miguel Montero last year, is confident he is up to the task at the major-league level.
He said his first full season in the majors ''just reaffirmed what I believed all the time. I have the ability to play here. It's confirmation in a way. I'm just excited to get out there and do it again.''
An intriguing option at catcher is power-hitting Peter O'Brien, who came in the trade that sent Martin Prado to the New York Yankees.
Already in informal workouts, O'Brien has put on quite a show in batting practice.
''You see guys in BP where if you see him hit a few home runs, you might yourself try to hit some home runs, might try to match him or whatever,'' Gosewisch said. ''But he's on a different level. He's fun to watch. It just sounds different coming off the bat. There's a few guys in the game that have that kind of sound and he's one of them. He's got some kind of power.''
However, O'Brien has defensive deficiencies that he's been working on over the past two months with Diamondbacks third base coach and former catching instructor Glen Sherlock.
''I'm really confident with where I am right now behind the plate,'' O'Brien said. ''Like I said, you make your strengths stronger and you keep working on your weaknesses and try to make them strengths too.''
Owings won't be in the mix in the early part of spring training as he recovers from shoulder surgery. When he returns, he should either get his shortstop job back or take the second base spot away from the veteran Hill.
If Owings goes to second, Hale had high praise for Ahmed's defense at short.
''We feel like defensively he's a guy as good as anybody in the major leagues,'' Hale said. '''... We have to work with him on certain hitting fundamentals and he's working hard at it.''
Hale said the transition of Tomas to third is ''going OK.''
''We're really not going to know how good he can be at third until we get in game situations and hitters are hitting balls at him,'' Hale said.
So there is plenty of evaluation to be done by Hale, chief of baseball operations Tony La Russa and general manager Dave Stewart.
''With all this competition, I think we'll sit back once games get going and watch these guys play,'' Hale said. '' Between Stew, Tony, myself and the staff, we'll sit down on a weekly, daily, nightly basis, whatever it takes, to evaluate it and take the best 25 over to Chase.''