The Washington Redskins are poised to make an aggressive effort in coming days to sign quarterback Peyton Manning, who became perhaps the highest-profile free agent in NFL history with the announcement of his release by the Indianapolis Colts Wednesday.

Several people familiar with the Redskins’ plans said the team is comfortable with the risks associated with signing Manning, who missed all of last season with the Colts after undergoing a series of neck surgeries. The team will pursue him intently, they said. Redskins officials declined to comment.

It also is unclear whether the possible addition of Manning would keep the team from pursuing a trade with the St. Louis Rams for the second overall selection in April’s NFL draft. The Redskins, who have the sixth overall pick in the draft, have appeared interested in trading up to use the Rams’ choice on Robert Griffin III, the Heisman Trophy-winning quarterback from Baylor.

One person with knowledge of the Redskins’ planning said the team intends to go after Manning aggressively and, if Manning signs elsewhere, turn its attention to strongly pursuing a trade for the Rams’ pick. But two others familiar with the Redskins’ intentions said signing Manning would not preclude the addition of a young quarterback in the draft--either Griffin or Ryan Tannehill of Texas A&M, who could be selected with the sixth pick.

At an emotional news conference Wednesday, Colts owner Jim Irsay and Manning said they had mutually agreed that now is the best time for the quarterback to leave the team, which has begun a major rebuilding of its roster.

“In life and in sports, we all know that nothing lasts forever,” Manning said.

Manning said he had not thought yet about where he would play next, but stressed that he is not ready to retire.

If the Redskins fail to land Manning, other options for a veteran free agent quarterback include Kyle Orton, the former Chicago and Denver starter most recently with the Kansas City Chiefs; and Matt Flynn, the Green Bay Packers’ backup to Aaron Rodgers, who could be highly valued by some teams in free agency.

The unrestricted free agent market opens Tuesday. But Manning gets a jump because he will be free to sign with any team once his release by the Colts becomes official. That could be as soon as later Wednesday or might happen Thursday. Manning was scheduled to earn a $28 million bonus if he remained on the Colts roster Thursday.

Irsay and Manning shared a flight Tuesday from Florida to Indianapolis.

The Colts have decided to overhaul their roster after going 2-14 last season without Manning, and are expected to use the top overall selection in the draft on Stanford quarterback Andrew Luck.

Any team interested in signing Manning will have to weigh the risks of giving a substantial contract to an aging quarterback coming off a serious neck injury against the rewards of adding the only four-time most valuable player in NFL history. Orthopedic surgeon Robert Watkins has pronounced Manning’s neck sufficiently healed for him to resume his career, but his arm strength remains a question.

Some observers have said that Manning’s throwing in his rehabilitation has been promising, and those who know the Redskins’ thinking said the team seems willing to absorb the risk of signing him.

Several people in the league said Wednesday they regard the Miami Dolphins as the frontrunner to sign Manning. The Dolphins seem intent on landing a top-tier quarterback and owner Stephen Ross appears willing to give Manning a contract with a significant amount of guaranteed money, those people said. Signing with the Dolphins would enable Manning to play in a warm, passing-friendly environment and would keep him in the AFC, although in the same division as his most obvious rival, the New England Patriots and their three-time Super Bowl-winning quarterback, Tom Brady.

The New York Jets and Arizona Cardinals also are widely regarded as strong contenders in the Manning sweepstakes. Playing for the Jets would put Manning, already one of the sport’s top endorsement pitchmen, on the big New York stage. He would share that market with his younger brother, New York Giants quarterback Eli Manning, but he would not have to compete with him on the field very often.

With the Cardinals, Manning would get to play his home games indoors and would inherit a top receiver in Larry Fitzgerald. The Chiefs, Seattle Seahawks and others also could attempt to sign Manning.

The Redskins don’t appear immediately equipped to satisfy Manning’s apparent desire to play for a team that gives him a good chance to make a successful return to the sport and chase a second career Super Bowl triumph. They went 5-11 last season and lacked a 1,000-yard receiver. Their offensive line remains a work in progress. And if Manning played for the Redskins, he would have to face his brother in two NFC East games per season.

One person familiar with the situation said Wednesday he wasn’t certain if Manning would consider an offer by the Redskins seriously because of those factors. But Manning and agent Tom Condon almost certainly would encourage the Redskins’ pursuit, that person said, in an attempt to intensify the bidding and raise the price tag for other teams.

But others said it’s possible the Redskins could be Manning’s best option, particularly if snags develop in his negotiations with other teams. One person who knows Manning said last week that Manning would be pleased with the organizational stability provided by Coach Mike Shanahan, a two-time Super Bowl winner in Denver, and General Manager Bruce Allen.

The Redskins, though, would have to address any concerns that Manning might have about their offensive system. Those who know Manning say he had great input into the way the offense was run in Indianapolis and would want to work in a similar system with a new team. Shanahan and his son, Redskins offensive coordinator Kyle Shanahan, failed to make things work with veteran quarterback Donovan McNabb after obtaining him in a trade with the Philadelphia Eagles before the 2010 season. But the Redskins might be more flexible with Manning, especially after totaling only 11 victories the last two seasons.

The Redskins also would have to demonstrate to Manning that they could put enough players around him to be successful, according to people who know Manning. That would include upgrading their wide receivers, something the team appears poised to do in free agency by trying to sign the San Diego Chargers’ Vincent Jackson, the Colts’ Pierre Garcon or the New Orleans Saints’ Marques Colston. The team that signs Manning also might end up with Garcon and Reggie Wayne, another former Indianapolis receiver who is a free agent.

A person close to one of the top free agent wide receivers said Wednesday that the Redskins must improve at quarterback before a high-profile wideout would sign with them.

More Peyton Manning news:

Manning news conference live blog

Jenkins: Get Manning

Reid: Pass on Manning

Manning’s options

Manning, Irsay fly home to Indy together

Weigh in: What should Redskins do?