THE GOOD NEWS is the Eagles have more than $45 million in salary-cap space heading into tomorrow's 4 p.m. start of the free-agency signing period, which is the fifth most in the league.

The bad news is, thanks largely to the $20 million increase in the salary cap over the last 2 years, they aren't the only team with a significant amount of spending room.

As of yesterday, 12 teams were sitting with at least $30 million in salary-cap space, according to spotrac.com. Nineteen had at least $20 million in cap room.

That said, the Eagles have managed to strike significant early blows in free agency, agreeing to tentative deals with their top free-agent target, Seahawks cornerback Byron Maxwell, and veteran 49ers running back Frank Gore.

The Eagles also agreed to terms with returning quarterback Mark Sanchez on a 2-year deal. Sanchez' deal is worth a minimum of $9 million and a maximum of $16 million, with $5 million guaranteed.

"I'm going to Philly," Maxwell told ESPN's Josina Anderson late yesterday afternoon, several hours after Houston radio talk-show host Jayson Braddock first reported that Maxwell had agreed to terms with the Eagles.

Free-agent deals can't be finalized until the start of the free-agency signing period tomorrow.

According to the Baltimore Sun, Maxwell's deal is worth $63 million over 6 years and includes a whopping $25 million in guaranteed money.

Maxwell, 27, has only 17 career starts in four seasons but is considered the top-rated corner on the free-agent market.

Now that they have Maxwell, it's not clear whether the Eagles will try to sign another corner in free agency or wait for the draft to add another one. Last year's two starting corners, Cary Williams and Bradley Fletcher, both are gone. Williams was released last week and Fletcher is an unrestricted free agent who isn't expected to be re-signed.

The Eagles also have landed the 31-year-old Gore, a five-time Pro Bowler who has spent 10 seasons in the league, all with San Francisco. A league source confirmed an ESPN report that Gore will sign a 3-year deal with the Eagles tomorrow that includes $7.5 million in guaranteed money over the first 2 years.

On Saturday, the Niners seemed reasonably confident that they would re-sign Gore. But $7.5 million in guaranteed money can be quite an aphrodisiac.

Gore has rushed for 11,073 yards in his career, averaging 4.5 yards per carry. One of the many things that appeals to Eagles coach Chip Kelly about Gore is that he seldom gets tackled for negative yardage. Last year, he rushed for 3 yards or more on 59.8 percent of his carries on first and second down, compared to 55.1 percent by ex-Eagle LeSean McCoy.

It's unclear how many other top-tier free agents the Eagles are pursuing. They have been linked to Patriots safety Devin McCourty and also need an edge rusher to replace Trent Cole, who was released last week. But they will have competition.

"There are lot of teams with a lot of cap room," said former Eagles president Joe Banner. "There are a few outliers in the $45 million to $65 million [cap space] range. But more significantly, there's a huge number that have $20-30 million in cap room. I mean, the amount of dollars in the market place is huge. And there aren't that many guys to spend it on.

"To think in any given year you're going to get a large number of really good players [in free agency], the market usually doesn't allow for that. Even if your evaluations are good and even if the price you're paying is reasonable, there's still a limited number of players in each market that can really make a difference. And there's 32 teams that are after them."

Because most teams have put a high priority on re-signing their own top young players, the free-agent market historically has been more about quantity than quality. But this year's crop actually appears to be deeper than previous ones, particularly at some of the Eagles' positions of need such as cornerback, edge rusher and interior offensive line.

The reason: With the increase in the cap giving so many teams so much additional cap room, agents have been encouraging their clients to test the market.

"If I were an agent, it would take a hell of an offer from a team for me to sign before hitting free agency," Banner said. "Because there's just going to be so much money that you're going to be surprised at the sizes [of the contracts]. You're going to look at players who are just decent and see them get money that's going to really surprise you.

"We saw it last year with guys like [Jairus] Byrd getting $9 million [per year]. It wasn't that long ago that people would have thought paying a safety $9 million a year was crazy. But the increases in the cap combined with the decreases in the rookie pool money has made that kind of thing plausible."

Cornerback Aqib Talib, boasting a lot of talent but a checkered off-the-field history, signed a 6-year, $57 million deal, including $25.5 million in guarantees, with the Broncos on the first day of free agency last year. He is among 10 corners in the league with a contract average of at least $9.5 million a year.

Assuming the reported details of Maxwell's deal are correct, he will become just the fifth corner in the league with a contract average of more than $10 million ($10.8 million), behind the Patriots' Darrelle Revis ($16M), the Cardinals' Patrick Peterson ($14.01M), the Seahawks' Richard Sherman ($14M) and the Browns' Joe Haden ($13.5M).

The $25 million in guaranteed money Maxwell will reportedly receive would put him fifth behind Peterson ($47.4M), Sherman ($40M), the Cowboys' Brandon Carr ($25.5M) and Talib. Not bad for a former sixth-round pick who had started just five NFL games before last season.

The proportion of guaranteed money given to players has skyrocketed in recent years. It's up to nearly 45 percent. Ten years ago, it was in the high 20s. It is expected to take another healthy jump this year.

Despite a history of injuries, nearly half of Byrd's 6-year, $54 million deal with the Saints last year was guaranteed. Another safety, T.J. Ward, had $14 million of the $22.5 million he received from the Broncos guaranteed.

Many fans think free agency isn't as much of a crap shoot as the draft because you're dealing with players that, in most cases, already have had some level of success in the league. But that hasn't been the case.

For a number of reasons, a player might thrive in one system but not another. Or he might be closer to the downside of his career than his new team realized. Many just aren't the same player after a team shows them the money.

"Most of the really good players in the league care about money, just like you do and I do and everybody else does," Banner said. "But that's not what primarily drives them. So you really want to try hard to hit on guys in free agency that you feel won't be overly focused on the money. You want to do your research and make sure that you're not getting a guy that once he gets the check won't be the same player."

When Banner was with the Eagles, the team did a study comparing the success rate of players in the first 2 rounds of the draft with veterans who signed in the first 3 to 5 days of free agency.

The gauge they used was whether the player started for at least 3 years after signing. According to Banner, the leaguewide success rate for both first- and second-rounders and top-tier free agents was almost the same: about 44 percent.

But the repercussions for guessing wrong on a first- or second-tier free agent are much more severe than for guessing wrong on an early-round draft pick.

"If you miss on a draft pick, hopefully you hit on another guy in the later rounds to make up for it," Banner said. "Either way, you move on.

"With a high-priced free agent, the consequences as far as carrying the guy who's a weak player and/or cutting him and then having to eat all of that dead money is much greater than missing on a draft pick, even though the success rate is about the same."

On Twitter: @Pdomo

Blog: eagletarian.com