While it had been assumed that the 27-year-old Mastny had the upper-hand in the battle, his inconsistency this spring, paired with some strong outings from the challengers, has kept things interesting.
Manager Eric Wedge said he expects a decision to be made before the Indians break camp in Florida on Thursday and head up to Atlanta for a final pair of exhibition games against the Braves.
"All three of them are different," Wedge said of the competitors. "They all offer you a different look."
Julio, 29, is the most experienced reliever of the bunch. Having served as Baltimore's closer from 2002-04, Julio has amassed 411 career relief appearances with the Orioles, Mets, Diamondbacks, Marlins and Rockies. He was 0-3 with a 3.93 ERA in 58 games for Colorado last season.
The Indians like that Julio is a hard thrower with late-game experience. He had a slight setback earlier this week, when a blister formed on his pitching hand. But the right-hander recovered quickly to pitch two scoreless innings against the Braves on Friday, lowering his spring ERA to 1.80 in 10 innings over eight appearances.
"He's had a real good spring," Wedge said of Julio. "He's been pretty consistent with his stuff, and he's gone out there and done a good job."
Elarton, 32, has been one of the bigger surprises in camp. It had been assumed the Indians signed him as a favor to showcase him to other clubs, but Elarton came in hungry to prove himself as a reliever, and he's done just that. He came into Saturday's game against the Mets, in which he was scheduled to throw an inning, sporting a 1.46 ERA in 12 1/3 innings over eight appearances.
If Elarton, a veteran starter, makes the club, it would be his first foray into Major League relief since 1999 with the Astros.
"Elarton is a guy that's going to do a good job with his fastball and work his secondary stuff off of that, with a lot of gut and a lot of drive in there," Wedge said. "He's shown himself to be pretty durable and resilient this spring."
Mastny's numbers haven't been quite as impressive. He has a 6.75 ERA in 12 innings over eight appearances, though the ERA is skewed by two outings against the Rays and Yankees in which he gave up a total of eight runs.
"Mastny's a young kid that's still learning to do what he needs to do to be a consistent pitcher at this level," Wedge said. "He's been a little bit back and forth. We've seen him throw the ball well at times, and other times he just hasn't had the type of command you want to see."
This might very well be a battle for a spot in which the appearances are spare. Given the depth of the back end of the Tribe's bullpen, and the general consistency of the rotation, the seventh man might be an odd man out, of sorts.
"It just depends on how things play out with your starters and other relievers," Wedge said. "It all stems from your starting pitching."