The Flames have cap space to burn and clearly wanted to dump the aging Tanguay's remaining salary and term on a team that was willing to give him another shot; Tanguay, who was signed as a free agent by the Flames prior to the 2010-11 season at the apparent request of Jarome Iginla, had his worst season points-wise in 2012-13 since his disastrous stint with the Lightning in 2009-10 (although in fairness, his season was cut in half this year).
Cory Sarich appeared in 28 games for the Flames last season, scoring two points for the club. The 34-year-old was re-signed to a two-year deal (with a no-movement clause) by the Flames last season, has had numerous injury problems (primarily with his foot, I believe), and has largely been a defensive liability playing anything but bottom-pairing minutes for the club.
The Flames acquire 28-year-old forward David Jones, who has played his entire career for the Avs, and much like Tanguay, struggled in the lockout shortened season, scoring just three goals and nine points in 33 games. Jones, a former ninth round draft pick of the Avalanche, will collect $4M from the Flames next season. His new deal came as a result of his 20-goal, 37-point season in 2011-12. The good news? Hockey Prospectus' Corey Pronman thinks he will bounce back and provide value to the team:
Jones took on very tough minutes this year for COL and got very unlucky. Not buying his goals/points this year as what he really is.
Jones took on very tough minutes this year for COL and got very unlucky. Not buying his goals/points this year as what he really is.— Corey Pronman (@coreypronman) June 27, 2013
Shane O'Brien, noted party-boy and frequent customer of Vancouver bar The Roxy, accumulated four assists and 60 PIMS in 28-games with the Avs last season. The 29-year-old will make $2M next year, mostly by sitting in the penalty box and coughing up the puck on the bottom-pairing, apparently. So him and Sarich are very much alike in that regard.
Overall, the Flames shed two players who are no longer very valuable to them in order to bring in one player who has the potential to offer them more valuable years. They didn't shed salary, but with a boat load of cap space, that's not necessarily a priority for them at the moment.