If you didn’t know by now, The Fix is skeptical that political endorsements matter much. If they matter at all. But if there’s one that has mattered in the 2012 presidential race to date, it might be that of Rob Portman.

Republican presidential candidate and former Massachusetts Governor Mitt Romney (C) tours Gregory Industries with Executive Vice President Matt Gregory (R) and U.S. Senator Rob Portman (R-Ohio) during a campaign stop in Canton, Ohio, over the weekend. (REUTERS/Brian Snyder)

And for a guy who got a fair amount of vice presidential buzz four years ago, it’s likely that Portman will be a major player in the veepstakes as the year goes on. (The Portman chatter is starting already.)

Romney’s team gives Portman lots of credit for helping win in his home state. Here’s why:

* While other candidates may lend their name to support a presidential candidate and then be done with it, Portman was regularly at Romney’s side at campaign events and even stepped in for him when Romney was unable to attend an event in Wilmington, Ohio.

* Portman had a real campaign apparatus in place from his 2010 Senate campaign, and that benefitted Romney greatly. Other recent endorsers also won in 2010 — Michigan Gov. Rick Snyder, South Carolina Gov. Nikki Haley and New Hampshire Sen. Kelly Ayotte, for instance — but Portman has been on the scene in Ohio for a long time and has cultivated much more of a political machine than those three, all who are relative newcomers to the big stage.

* The race in Ohio was close. With Romney winning by 1 percent of the vote, it’s not unreasonable to think that, without Portman’s help, he would have lost. Romney took his highest share of the vote in Hamilton County in Southwest Ohio — which Portman represented in the House — and netted more than 15,000 votes there, which was bigger than his overall margin statewide.

“We had about a 30,000-vote plurality” in southwest Ohio, Portman noted Wednesday in an interview on Capitol Hill. “That 30,000 obviously was critical, with the 10,000- or 11,000-vote victory statewide.”

Snyder also presided over a close Romney win last week in Michigan, but he isn’t as broadly popular in Michigan, is just beginning his political career, and the result wasn’t as close as it was in the Buckeye State.

In fact, about the only politician that may have benefitted Romney as much as Portman so far in the race was another potential vice presidential candidate: Florida Sen. Marco Rubio. Rubio didn’t actually endorse Romney, but he did do the former Massachusetts governor a solid when he criticized an ad being run by Newt Gingrich that labeled Romney as “anti-immigrant.” Romney’s team says that Rubio’s condemnation was a big turning point between his loss in South Carolina’s primary and his big win in Florida.

So why isn’t Portman getting the same kind of vice presidential buzz as Rubio at the moment?

It almost seems, by some weird twist, that being elected to the Senate in 2010 has hurt Portman because now he’s just a freshman senator alongside some more exciting freshmen senators — Rubio and Ayotte being two.

But just because Portman isn’t the shiny new thing on the political scene doesn’t mean he’s not a viable option for Romney or anyone else when it comes to running-mate material. Portman is very well-respected in GOP circles and brings to the table a wide resume — particularly on economic issues — that could look good next to a longtime businessman like Romney.

Not to mention the fact that Portman on the ticket could be the boost — even at the margins — that could put Republicans over the top in the swing state of Ohio.

That said, there still reason to be skeptical that Portman will get the vice presidential bump.

One potential problem: Portman was at the head of OMB during a time when the country wracked up a good deal of the massive debt in which we currently find ourselves. His supporters note that the budget deficit in 2007 (when he was at OMB) was a relatively small $161 billion, but for a party trying to turn the page on the Bush era, bringing Portman on board might impede that effort.

Second, besides being from Ohio, he’s not a great complement to Romney personality-wise. Portman is very understated and doesn’t have a terribly compelling personality, which could be an issue, given Romney’s problems exciting conservatives. Put plainly: If Republicans are looking for someone exciting, Portman simply isn’t it.

Portman also has considerable personal wealth (between $1.3 million and $16.3 million on his most recent personal financial disclosure form), which wouldn’t necessarily play well next to Romney’s vast personal wealth. Given that the Obama campaign has shown it’s ready to play up Romney’s wealth and campaign against the “1 percent,” it’s probably not a great idea for the GOP to field two candidates who come from the that 1 percent.

For his part, Portman isn’t publicly lobbying for the job.

“No, not for me,” he said Wednesday.

But in politics, trust and results matter a lot, and if Romney’s team truly believes Portman gave it a win in Ohio on Tuesday — a win that likely saved them LOTS of trouble going forward — that’s going to mean a lot.

Whether that makes Portman a vice presidential contender or not, it will at least make him a key player.

Ed O’Keefe contributed to this report.