PEORIA, Ariz. -- When Rockies catcher Tom Murphy relaxes, the ball flies.
Murphy launched a low Mike Leake fastball beyond the 410-foot mark in center field in the fourth inning of the Rockies' 3-2 Cactus League victory over the Mariners on Tuesday night.
"It seems like the less effort that I put into may swing, the more the ball seems to do that," Murphy said.
It was the second spring home run for Murphy, who is vying for opportunities behind veteran Chris Iannetta. Murphy hit .257 and demonstrated power with three homers and a .543 slugging percentage in 11 games during his first callup in 2015, but he suffered a broken wrist and forearm when accidentally struck by a bat last year during Spring Training.
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After he regained his health, Murphy pressed and struggled, hitting .255 with four homers and 56 strikeouts in 141 at-bats at Triple-A Albuquerque and going 1-for-24 in 12 Major League games.
A third-round pick out of the University of Buffalo in 2012, Murphy thought he was applying pressure to meet perceived expectations. He vowed to stay calm this spring.
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"That's probably been the most successful part of my spring, regardless if anybody knows that or not," Murphy said. "It's one of those things that's going to be personal and internal. I feel my internal clock is working well, and I will be successful."
Manager Bud Black said he and Rockies bench coach and catching instructor Mike Redmond have been working with Murphy to improve his defense and are seeing results.
"Just the way he is receiving the ball, the way he's moving behind the plate, is much better -- different setup, different stance that we felt was very important for him," Black said. "Offensively, he's a tireless worker in the cage with our hitting coaches. Hopefully, he'll bounce back."
Electric stuff
Rockies starter German Marquez struck out four in three innings, giving up one run on three hits against the Mariners on Tuesday night. After not being happy with his velocity in his first spring outing, Marquez hit 97 mph with a fastball, mixed in four changeups (a developing pitch) and several curves and finished strikeouts with some nasty pitches. One was a curve that bounced and skipped past Murphy to let Cameron Perkins reach. Marquez also threw a fastball that cut -- by mistake rather than design -- to strike out Nelson Cruz. That one sailed past a surprised Murphy, who retrieved and threw to first in time.
"I'm going to keep working on my changeup and the slider," Marquez said. "I want those pitches to be really good in the season."
Expanding skills
Righty-hitting Daniel Castro, a non-roster player hoping to earn Major League time as a utility player, went 3-for-3 on Tuesday and is batting .368 this spring. Castro appeared in 80 games with the Braves in 2015 and '16, but he spent all of last season with the Rockies' Triple-A Albuquerque squad.
But Castro, 25, made the most of the time in Albuquerque. Castro has classic range at shortstop, and with fellow non-roster player Shawn O'Malley nursing a broken left hand, he could be a fill-in option if the team finds itself without Trevor Story. But after hitting .217 with the Braves, Castro knew he needed to improve his offense to be a feasible big league option.
Working with Albuquerque hitting coach Darin Everson, Castro eliminated a leg kick, which helped his timing. The Rockies liked him enough to prevent him from leaving as a free agent.
"I felt with this team, I have the best opportunity to get back to the big leagues," Castro said in Spanish. "They saw me play last year and wanted me back."
Injury update
Righty Carlos Estevez (left side injury) reported feeling increasingly good throwing long toss, but he'll need bullpen sessions and a simulated game without a screen before being a candidate for a Cactus League game.
Position competition
• Outfield hopeful Mike Tauchman lashed an RBI triple into the right-field corner and scored on the play when the Mariners' Cameron Perkins spiked the throw and watched in horror as the ball bounced over the fence and out of play. Mariners pitcher Mike Leake noted: "He said he was about to throw it, but he had some dirt in his hand. So he didn't want to throw it and next thing you know, it was spiked. That was a five-story spike."

• Looking fully back from 2016 Tommy John surgery, righty reliever Jairo Diaz struck out two of the three hitters he faced Tuesday and has three scoreless innings with four strikeouts. 
• Ryan McMahon, trying to prove he's ready to play first base, got the start at third base Tuesday and went 1-for-3. He is hitting .393, with a few hits like Tuesday's dribbler up the middle, but some solid passes, as well.
Up next 
Righty Antonio Senzatela will throw four innings and righty Peter Lambert -- the club's No. 5 prospect, according to MLB Pipeline -- is scheduled for two innings in his third A-game Wednesday at 1:10 p.m. MT against the Rangers at Salt River Fields. Closer Wade Davis and bullpen righties Scott Oberg and Adam Ottavino also are scheduled.
Additionally, righty starter Chad Bettis will start against the Angels in a 10 a.m. "B" game at the Rockies' complex. Also scheduled are lefty relievers Mike Dunn and Jake McGee, righty non-roster reliever Brooks Pounders, who has four strikeouts in four innings, and No. 14 prospect, righty Jesus Tinoco.