2002-03: Calla played in the Westside minor hockey association and was selected by the Everett Silvertips in the fourth round of the 2003 WHL bantam draft.
2003-04: Calla made his WHL debut with Everett appearing in three games.
2004-05: Calla appeared played his first full season with Everett in the WHL, scoring 11 goals with 10 assists and was +6 with 38 PIM in 68 games. In eleven playoff games with the Silvertips, he scored 1 goal with 1 assist and was -2. Calla played for Canada Pacific in the U-17 Junior Challenge and scored 2 goals with 4 assists in six games.
2005-06: In his second season with Everett, Calla played most of the season alongside Zach Hamill and team scoring leader John Lammers (DAL). Calla scored 8 goals (three on the power play) with 25 assists and was +7 with 52 PIM in 66 games. In 11 playoff games, he scored 1 goal with 2 assists and 4 PIM and was an even plus/minus. Calla was a member of Team Cherry at the 2006 CHL/NHL Top Prospects game.
2006-07: Calla started the season with Everett before a mid-season trade to Moose Jaw. While the Warriors failed to make the playoffs, while Everett finished first in the U.S. division, the move proved beneficial to Calla as he was able to play a lot more and was used in all situations by Moose Jaw. In 68 games between the two teams, Calla scored 15 goals with 26 assists and was +7 with 42 PIM, but had just nine points in 29 game and was -5 while with Everett.
2007-08: Calla was once again involved in a mid-season trade, swapping teams with fellow Panthers prospect Keaton Ellerby (FLA) and going from Moose Jaw to Kamloops. Calla got off to a quick start offensively with Moose Jaw, scoring 2 goals with 8 assists and 10 PIM in 14 games. In 52 games with Kamloops he scored 10 goals (five on the power play) with 20 assists and 50 PIM and was -20 on a sub-.500 Blazers team. Despite their losing record, the Blazers qualified for the WHL playoffs but were quickly eliminated in the first round by the Tri-City Americans. In four playoff games, Calla had two assists and was -3 with 4 PIM. Calla signed a three-year deal with the Panthers in May and made his professional debut with their AHL affiliate in Rochester following the WHL playoffs. Calla scored 2 goals with 2 assists and was +3 with 2 PIM in six games with the Americans.
2008-09: Calla began the season in the AHL with the Amerks and had 1 assist with 9 PIM before being returned to junior hockey. Calla scored 5 goals with 8 assists and was +8 with 31 in 19 games with Kamloops before being traded to Spokane. In 31 games with the Chiefs, he scored 11 goals (five on the power play) with 14 assists and was +10 with 27 PIM. Calla scored 1 goal with 3 assists and was +4 with 6 PIM in the playoffs as the Chiefs defeated Seattle in the first round and then lost a memorable seven-game series with Vancouver in the second round – with the last three games all ending in overtime.
2009-10: Calla saw limited ice time with Rochester in his first full season of pro hockey. Alternating between fourth line duty and being a healthy scratch, Calla scored his only goal of the season in December and finished with 1 goal with 5 assists and was -7 with 14 PIM in 33 games with the Amerks. Calla was sent to the ECHL Florida Everblades in February and scored 2 goals with 2 assists and was +5 with 23 PIM in 16 games.
Calla is a character player and good skater who is willing to sacrifice for team success. Calla's puck skills need improvement and he's small for a checker. Calla is willing to do all the things necessary for a team to win, such as blocking shots and killing penalties.
Calla's enters the final year of his entry-level contract with the Panthers and will be hard-pressed to crack the Rochester lineup with a number of prospects recently signed to contracts. To his credit, Calla is willing to do all the little things to help his team win. With limited upside, Calla projects as a fourth line forward at best at the NHL level. But that is a long shot at this point.