There’s a budding recovery taking shape in Greater Boston’s battered office market, but for the most part, you won’t see it gazing at the skyline.

Except for Liberty Mutual’s unusual decision to spring for a new Back Bay headquarters, it could be a decade before the next skyscraper appears in downtown Boston.

Instead, pay close attention next time you walk through the tall timber of the Financial District and the Back Bay, where construction crews are revamping lobbies, replacing windows and installing high-tech elevator systems. Or take a look as you drive along Route 128, where a big revamp of one of the suburbs’ marquee office developments may soon be in the works.

While the amount of empty office space is still staggeringly high, developers and real estate investors are poised to pump hundreds of millions into upgrades to aging towers and high-profile suburban office complexes.

It’s a high-stakes bet that the worst may finally be behind us – and it just may pay stunning dividends if the Boston office market follows its typical pattern climbing out of this downturn.

“They want to make the building a strong option to corporate tenants out there – and they are willing to invest to attract those tenants,” said Benjamin Heller, executive vice president of Jones Lang LaSalle, of the tens of millions of dollars TIAA-CREF has pumped into 99 High St.

Betting On The Future

So who’s betting on the future of the Greater Boston office market amidst one of the steepest real estate downturns in generations? It’s a cast that includes a hometown real estate giant and one of the nation’s largest pension funds:

Boston Properties has agreed to upgrade the iconic John Hancock Tower as part of its blockbuster $930 million acquisition deal. Out in the suburbs, the talk of the town is that BXP is also poised to pump big bucks into the recently acquired Bay Colony Corporate Center in Waltham, one of Route 128’s best known suburban office complexes.

Chicago-based real estate investor Heitman has pumped millions into a snazzy new lobby and other upgrades at 260 Franklin St., a Financial District stalwart that had lost some of its luster. That project wrapped up last month.

Teachers pension giant TIAA-CREF is digging deep to fix up 99 High St., which now has a new lobby and will soon have 1,000 new windows as part of a $30 million overhaul, set to be complete by early 2011.

Commonwealth Development, the local builder who bought the old Verizon telephone building at 185 Franklin St., is planning a sweeping revamp of that Financial District high-rise after it lines up an anchor tenant.

Now if this all seems like madness, you are to be forgiven. After all, the agonizingly slow economic turnaround is not yet etched in stone, and a spike in the jobless rate could spell serious trouble for tower owners everywhere.

Moreover, some of these tower owners are pumping millions into addresses scrambling to fill big blocks of empty space. For example, the owner of 260 Franklin, having spent big on an upgrade, now faces the challenge of having to fill 20 percent of the tower.

Right On Target

Still, for downtown office tower owners who can scrape together the cash, undertaking an extreme makeover now is likely to be a shrewd strategic move down the line.

The current industry buzz right now is that we won’t see another new tower get under construction until 2014 – if we are lucky.

Coming out of the 2001 recession, downtown tower developer Dean Stratouly wrapped up work on 33 Arch St., then made waves with an unusual prediction for a guy who builds things for a living: No new towers for the rest of the decade.

He was scoffed at by some, but he turned out to be right on target.

There’s no reason to think history won’t repeat itself again – Boston, after all, is probably the toughest market in which to build a new tower anywhere in the country. There are few sites left to build on, and getting your project through the gauntlet of at-times meddlesome city officials and aggressive neighborhood groups is no small matter, either.

And we haven’t even gotten to rents yet. Corporate suites in some top towers are going for less than $50 a square foot – rents will have to push into the $70-a-square foot range before building a new tower makes sense.

“The one thing I can say about new development is that the market fundamentals are not going to allow you to put anything in the ground anytime soon,” said Paul Leonard, research manager at Jones Lang LaSalle.

However, for office tower owners spending millions on upgrades to half empty towers, that’s not bad news. It means competition from a shiny new tower or two right now is a distant threat.

Meanwhile, big blocks of empty space in top towers like International Place and 75 State St. will get gobbled up as the economy revives. And that will inevitably lead to bidding wars for increasingly scarce space among tenants, which will lead to soaring rents.

“There are a lot of really nice buildings that have some terrific options,” said William McCall, president and principal of McCall & Almy.

And all those tower owners who looked a little crazy today will suddenly be looking pretty smart tomorrow.