2006-07: Jaroslav Janus split the season between the HC Slovan Bratislava U-18 and U-20 junior teams in his native Slovakia. In 35 games at the U-18 level, he had a 2.51 GAA and .906 save percentage. He played 24 games with the U-20 team and allowed 2.14 goals per game with a .935 save percentage. Janus handled the bulk of the goaltending duties for fifth-place Slovakia at the WJC U-18 tournament in Finland and was 2-3 with a 3.14 GAA and .921 save percentage. Janus was selected by the Erie Otters of the OHL in the first round (2nd overall) of the 2007 CHL Entry Draft.
2007-08: Janus was under constant seige during his first season in North America on an Erie team that had the OHL's second-worst record. He finished with 13-29 with 3 OT losses with a 4.40 GAA and .892 save percentage, facing 1867 shots in 48 games. Janus was eligible for the 2008 NHL Entry Draft, but was not selected.
2008-09: Janus' second season with the Otters was much more enjoyable as the Otters had a winning season and finished third in the Midwest Division. Janus was in the top 10 in the OHL in wins, save percentage, and shutouts as Erie reached the playoffs for the first time since 2004-05. Janus finished 25-20 with 4 OT losses and 3 shutouts with a 3.24 GAA and .908 save percentage in 49 games for Erie. His lone win in the playoffs was a 4-0 shutout of London in Game 3 as the Knights eliminated Erie in five games. Janus finished the playoffs 1-4 with a 4.21 GAA and .898 save percentage. Janus virtually stole the show for Slovakia at the WJC, playing a large part in Slovakia's upsets over Finland and the United States en route to a fourth-place finish. Janus was 3-3 in six games with a 3.20 GAA and .900 save percentage and was named to the tournament all-star team.
2009-10: Janus split the season between between Tampa Bay's AHL affiliate Norfolk and Erie in the OHL. He started two games with the Admirals in October – losing both despite allowing just three goals – before the Lightning returned him to juniors. He was signed an entry-level contract with Tampa Bay in January and spent the rest of the season playing in tandem with fellow Lightning prospect Dustin Tokarski. After losing his first three starts following the call-up, Janus won 7 of 8 starts to finish the season including a 24-save shutout of the Lowell Devils on February 12. His overall mark with Norfolk was 7-6 with a 2.07 GAA and .922 save percentage. In 13 OHL games with Erie, Janus was 7-4 with 2 OT losses and a 2.81 GAA and .918 save percentage.
2010-11: Janus spent most of his first full season in pro hockey with the ECHL Everblades; appearing in nine games for Norfolk (AHL). Janus made two spot starts for the Admirals before joining them for good in late March and finished 2-6 with a 3.64 GAA and .872 save percentage. Janus was with the Admirals for the AHL playoffs but did see any action. In 27 ECHL games with Florida he was 12-13 with a 3.06 GAA and .912 save percentage.
2011-12: Janus appeared in 34 games while splitting the goaltending duties with Dustin Tokarski for Lightning AHL affiliate Norfolk. He was 23-8-2 with 1 shutout and had a 2.36 goals against and .914 save percentage. The Admirals finished first in the East Division and won the AHL's Calder Cup. Janus appeared in four playoff games as Tokarski handled the bulk of the goaltending and was 3-1 with 1 shutout and a 1.69 goals against and .937 save percentage.
2012-13: Janus returned to Europe — skating for Slovan Bratislava in the KHL on loan from the Lightning— and played for Slovakia in the 2013 IIHF World Championship. In 47 KHL games he was 18-16-13 with 5 shutouts and had a 2.17 goals against and .928 save percentage. Slovan finished third in the Bobrov Division and was swept by Dynamo Moscow in a first round series. Janus was 0-2 and had a 4.03 goals-against and .867 save percentage in two playoff games.
Janus, like fellow Lightning prospect Tokarski, is undersized compared to most goalie prospects. He is not quick, but is an aggressive goaltender that has no problems coming out of his crease to make himself look bigger. Janus never quits on a scoring chance and sometimes makes highlight reel saves in desperation. Perhaps his most outstanding quality is his mental game as Janus thrives in high-pressure situations.
Janus and Dustin Tokarski are very similar prospects in that neither have ideal NHL size but both have been productive and have the ability to give their team an opportunity to win. Many organizations are reluctant to consider going with a smaller goalie due to the high quality shooters in the NHL, but Janus, like Tokarski, has the skill level to one day start at the NHL level if given an opportunity.