Angerer has decided to retire from football, NFL.com reports.

Angerer was selected in the second round of the 2010 Draft by the Colts and quickly became a key contributor for Indianapolis. In fact, his career-high 148 tackles (78 solo) in 2011 ranked fourth league-wide. However, since then, Angerer has endured multiple concussions and underwent microfracture knee surgery last December. To preserve his future health, Angerer has chosen to retire, finishing his four-year career with 327 total tackles.

Angerer has been released by the Falcons, the Atlanta Journal-Constitution reports.

Angerer, who is bouncing back from microfracture knee surgery in December, may resurface elsewhere if he can re-establish his health, but the report hints that the 27-year-old linebacker's NFL career could be at the end of the line.

Angerer tallied five tackles in limited work in Saturday's preseason contest against the Texans.

Angerer had been dealing with a concussion he suffered earlier in training camp, but he appears to have passed all the necessary protocols. He isn't expected to beat Paul Worrilow or Joplo Bartu out for a starting role, but he'll likely see some rotational work if he stays healthy.

Angerer is dealing with a head injury, and he will be subject to the NFL's concussion protocol.

The oft-injured Angerer dealt with a concussion last September, but he doesn't seem to have a notable history of head injuries. With Sean Weatherspoon (torn Achilles) out for the season, Angerer seemingly has a chance to earn some playing time, though the Falcons are expected to start second-year players Paul Worrilow and Joplo Bartu.

Falcons signed LB Pat Angerer.

Angerer is apparently over the knee injury that ended his 2013 and required offseason surgery. Injuries have limited the 2010 second-rounder to just 11 appearances in each of the past two seasons, but he'll have a good shot at cracking the 53-man roster if he can remain healthy. The Falcons are ad libbing as they look to make up for the loss of ILB Sean Weatherspoon (Achilles').

Free agent ILB Pat Angerer worked out for the Falcons on Tuesday.

Angerer, 27, ended last season on injured reserve with the Colts due to a knee injury that required offseason surgery. His workout with the Falcons is his first nibble of action since. The former second-round pick has also battled concussion and foot problems the past two years. Atlanta is simply looking for bodies after losing ILB Sean Weatherspoon to a torn Achilles' in the spring.

Free agent ILB Pat Angerer is recovering from microfracture surgery, and "still a few months away" from conducting workouts.

Angerer claims he received interest from "several teams" earlier this offseason, but wants to hold off on free-agent visits until he's 100 percent healthy. Angerer was oft-injured during his four years in Indianapolis, dealing with multiple knee and foot issues. Angerer played 501 largely-ineffective snaps last season before landing on injured reserve in December.

The Colts are not trying to re-sign free agent ILB Pat Angerer.

The Colts are looking elsewhere to fill the hole next to Jerrell Freeman. In-house options include Josh McNary and Kelvin Sheppard, and they're also in the mix for free agent D'Qwell Jackson. Angerer was a tackle machine when healthy for the Colts, but knee and foot injuries have crippled the 2010 second-round pick.

The Indy Star says the odds favor the Colts moving on from free agent ILB Pat Angerer.

Even though the Colts have a hole next to Jerrell Freeman at inside linebacker, they don't appear to believe Angerer is the answer. The 2010 second-round pick has missed 10 games over the last two seasons and Josh McNary/Kelvin Sheppard have been just as effective. Angerer's market will be cool.

Colts placed ILB Pat Angerer on injured reserve, ending his season.

Angerer was a healthy inactive in Week 15, but dealt with a knee injury earlier this year. He'll finish 2013 with 63 tackles, 0.5 sacks, and an interception over 11 games (nine starts) and will be an unrestricted free agent this offseason. The Colts have signed veteran RB Shaun Draughn to replace Angerer on the active roster.

Colts ILB Pat Angerer (knee) is probable for Week 4 against the Jaguars.

Angerer returned to practice Wednesday and hasn't had any setbacks. He'll immediately regain his starting job over Kelvin Sheppard and Kavell Conner. Angerer missed last week's game with a knee injury, but it was never a major concern.

Colts ILB Pat Angerer (knee) is practicing Wednesday.

Angerer missed Week 3 with a knee injury, but it was never a major concern. He's on track to return for Sunday's game against the Jaguars.

Colts ILB Pat Angerer (knee) has been ruled out for Week 3 against the 49ers.

Angerer missed Week 1 with a concussion before returning to play 58-of-66 snaps last week against the Dolphins. Frank Gore is a borderline RB1 this week.

Colts ILB Pat Angerer is listed as doubtful for Week 3 with a knee injury.

Colts SS LaRon Landry (ankle) has been ruled out, and FS Antoine Bethea (toe) is questionable. Vernon Davis and Frank Gore are set up for big Week 3s.

Colts ILB Pat Angerer (concussion) will return to the lineup in Week 2.

The Colts have been intent on starting Angerer over Kavell Conner, who is still battling an ankle injury. So look for Angerer to get the first-team nod next to Jerrell Freeman as Indianapolis hosts the 1-0 Dolphins.

Colts ILB Pat Angerer (concussion) has been medically cleared.

Angerer returned to practice Wednesday. His role for Sunday's game is unknown as starter Kavell Conner (ankle) remains day to day.

Colts ILB Pat Angerer is in danger of missing Week 1 due to concussion-like symptoms.

Angerer suffered the concussion in Indianapolis' preseason finale. The Colts could be down to their No. 4 inside linebacker next to Jerrell Freeman, as Kavell Conner (ankle) is out for Week 1. The No. 4 option is Kelvin Sheppard.

Colts activated ILB Pat Angerer (foot) from the active/PUP list.

Angerer missed the entire offseason program after undergoing foot surgery, but should get some reps in the preseason. The former starter is currently projected as depth behind Jerrell Freeman and Kavell Conner.

Colts placed ILB Pat Angerer (foot) on the active/PUP list.

Angerer missed OTAs and minicamp while recovering from offseason foot surgery and remains without a timetable to return. He should provide depth behind Jerrell Freeman and Kavell Conner once healthy. Angerer is set to make $630,000 in the the final year of his rookie contract.

Colts ILB Pat Angerer (foot) is not participating in this week's OTAs.