Uncertainty reigns as deadline nears

We expect ace pitchers to dominate the trade deadline conversation — CC Sabathia did it in 2008, Roy Halladay in 2009, Cliff Lee in 2010, Ubaldo Jimenez in 2011 and Zack Greinke in 2012.

The names change, but the nature of the discussion does not. We try to determine the identity of This Year’s Guy, and then watch as the moves (or at least the rumors) spin off that hub.

Not so in 2013. With the non-waiver deadline looming at 4 p.m. ET Wednesday, this has been one of the most decentralized trading seasons of the past decade. Matt Garza’s move from the Cubs to the Rangers was significant, but we’re still waiting for the aftershocks ... which started with the Chicago White Sox sending Jake Peavy to the Boston Red Sox on Tuesday night.

One reason for the uncertainty is that a number of teams who should sell — namely the Phillies, Giants, Blue Jays and Angels — entered the year with postseason expectations and have been slow to concede.

Another is that we’re in Year 2 of the second wild card, which discourages bubble teams from taking apart their rosters (the Kansas City Royals, at 51-51, are one such example). This should prompt Major League Baseball to consider the possibility of an Aug. 10 or Aug. 15 non-waiver trade deadline, but that is another column for another day.

For now, it’s my duty to prepare you for these final, frenzied hours before the deadline. Among the key storylines to watch:

Will one player — or one seller — shift the landscape?

The Phillies have received considerable media attention over the past few weeks, and understandably so. In Lee, Chase Utley, Jonathan Papelbon and Michael Young, they have recognizable players who could be dealt en masse if general manager Ruben Amaro Jr. decides the time has come for a reboot. The argument to stand pat has become less tenable now that the Phillies have dropped eight straight.

Lee’s value is tempered somewhat by his recent neck stiffness and the $62.5 million (minimum!) left on his contract after this year. The combination of injury risk and a sizeable contract could make Lee a better candidate for the August trading period, since there’s a good chance he will clear waivers.

Thus, this week’s game-changer — if there is one — may need to come from outside Philadelphia. Toronto general manager Alex Anthopoulos is known for a willingness to discuss virtually any trade proposal. Multiple executives in the league told me recently they doubt Anthopoulos would move Jose Bautista or Edwin Encarnacion. The chances he would do so appear very remote. But what if an offense-starved team — such as Texas — is underwhelmed by the readily available bats and calls Anthopoulos with an enticing prospect package?

One revelation from the weekend: Our Ken Rosenthal confirmed Jeff Passan’s report that the Angels are willing to listen to offers for infielders Howie Kendrick and Erick Aybar. That’s noteworthy, given the thin market for middle infielders. But it will be difficult for general manager Jerry Dipoto to find a taker for Aybar, who has a .699 OPS this season and $8.5 million in salaries in each of the next three years, according to Cot’s Baseball Contracts.

Are the Pirates ready to part with top prospects in their effort to make the playoffs for the first time two decades?

Pirates GM Neal Huntington is in an enviable yet precarious position: His team is likely to finish with its first winning record since 1992, an outcome Pittsburghers would have welcomed when the season began. But now that the team has the National League’s second-best record, 82 wins won’t satisfy the fans any longer.

As charmed as the Pirates’ season has been, they have genuine roster concerns to address. They have the worst production in right field of any team in the NL. Closer Jason Grilli is on the disabled list with an arm injury and may not return until September. Rookie starter Gerrit Cole could be idled late in the season because of an innings limit.

The defending champion Giants could fulfill each of those needs: a starter (Tim Lincecum), a late-inning reliever (Javier Lopez or Sergio Romo) and a right fielder (Hunter Pence). The Pirates and Giants have had trade discussions this month, according to major league sources, and San Francisco general manager Brian Sabean has become more willing to sell now that his team is an NL-worst 7-16 in July.

So far, though, the Pirates have been unwilling to trade their top prospects: right-handers Jameson Taillon and Nick Kingham, outfielder Gregory Polanco and shortstop Alen Hanson. But it might be worth doing so if the Pirates can acquire multiple Giants with World Series-winning pedigree.

Are the Tigers the lone buyer in the American League Central?

We know the Tigers would like to add a bullpen arm to help with their playoff push. They’ve spoken with the Texas Rangers about closer Joe Nathan, although it doesn’t appear the talks have much momentum. The Rangers likely would want a major-league ready outfielder in return — Avisail Garcia or Nick Castellanos — and the Tigers may deem that to be too great a price for the 38-year-old Nathan.

The Tigers’ greater intrigue could be with their middle infielders. Second baseman Omar Infante has been on the disabled list nearly all month, and shortstop Jhonny Peralta has been mentioned in reports about the Biogenesis probe. If Peralta is suspended, club president/general manager Dave Dombrowski may need to consider outside options at shortstop — of which there are few.

The Indians and Royals face complicated decisions of their own, but for different reasons.

The Indians — three games behind Detroit in the division, only one back of Baltimore for the second wild card — have a better chance of making the playoffs than they might have expected when the season began. Cleveland needs another top-level starting pitcher if it wants to compete with Detroit down the stretch, but GM Chris Antonetti must decide whether the postseason opportunity is real enough that it merits parting with prospects.

The Royals, meanwhile, have won six straight and moved from “likely sellers” to “hold” — and maybe even “buy.” A few days ago, Kansas City’s Ervin Santana looked like a great candidate to be dealt — and for a high-end prospect package, thanks to his 3.06 ERA in the American League. But the price for Santana has seemed to rise with each victory, and now GM Dayton Moore seems ready to keep Santana for a long-shot chance at a playoff berth.