Bryce Brentz is one of the Red Sox' top power-hitting prospects. (Jim Allen/Portland Sea Dogs)

Whether or not John Farrell leaves Toronto to become the Red Sox manager — at a time when he has a season remaining on the three-year contract he received to manage the Blue Jays after the 2010 season — could well hinge on whether the team teams can agree on what comprises fair value when it comes to the skipper.

As explored ad nauseum last offseason, there are few comparisons when it comes to trades involving decision-makers (either baseball executives or managers) for players. But the two deals that got done last year, at least, suggest that the cost of such a “trade” does not include an elite prospect.

The Red Sox, of course, received two relievers from the Cubs for Theo Epstein, who left Boston to become president of baseball operations with the Cubs. The Sox got right-hander Chris Carpenter — a pitcher with a big arm who projected as a near-major league-ready bullpen contributor — as well as right-hander Aaron Kurcz — a small reliever who likewise has a big arm with impressive strikeout rates in the minors. The Sox parted with Jair Bogaerts, the twin brother of Xander Bogaerts, who was subsequently released by the Cubs.

Meanwhile, the Marlins sent a pair of prospects to the White Sox in order to secure the services of manager Ozzie Guillen. Florida sent right-hander Jhan Marinez and infielder Osvaldo Martinez to Chicago.

Baseball America ranked Marinez as the fourth-best prospect in the Marlins system entering the 2011 season while Martinez ranked fifth, leading to suggestions that equivalent compensation from the Red Sox to the Blue Jays might feature right-hander Anthony Ranaudo and outfielder Bryce Brentz, who ranked fourth and fifth in the Sox’ system in Baseball America’s pre-2012 rankings. But the comparison rings false.

“You’ve got to look at the quality of the players the Marlins gave up and not the ranks,” said Baseball America executive editor Jim Callis.

The reality of Martinez and Marinez is that their ranks reflected the absence of talent in the Marlins system. Marinez ranked fourth in the Marlins system and sixth in the White Sox’ system prior to this season because Baseball America viewed both farm systems as ranking among the worst in the game. Marinez’ likely upside is as a setup reliever. He has a high-octane fastball that can touch the high-90s, a slider and command issues. At the time that he went to Chicago, he was coming off a year in which he put up impressive strikeout numbers (11.5 per nine innings) and ugly walks totals (6.5 per nine).

Similarly, Martinez ranked as high as fifth prior to the 2011 season because he was coming off a strong year in Double-A, and he was in a farm system that had a few impressive prospects at the top but little below that surface. At the time that he went to Chicago, he was coming off a bad year in which he hit .245/.296/.322/.618 in the offense-inflating Triple-A Pacific Coast League and then was even worse in the majors, going 3-for-23 with neither a walk nor an extra-base hit at the end of the year. His strong defensive credentials pegged Martinez as little more than a utility player, unless he surprised by bouncing back to a 2010 season in which he performed at a level — .302/.372/.401/.773 in Double-A, .326/.383/.465/.848 in 14 big league games — that is an extreme outlier at this point in his career.

Who would be equivalent players in the Red Sox’ system?

For Marinez, the Sox have a few power arms that are close to big league ready, among them: Carpenter (and yes, everyone thinks it would be fascinating if he became the first player ever traded multiple times for non-players), right-hander Alex Wilson (who spent all of 2011 in Pawtucket) and right-hander Josh Fields (who finished his year with 13 2/3 scoreless innings in Triple-A Pawtucket, striking out 19 and walking two in the process).

For Martinez, the Sox have a pair of comparable players in Pedro Ciriaco (who hit .293/.315/.390/.705 with 16 steals in 76 games for the Sox) and Ivan De Jesus Jr., who went 0-for-8 with six strikeouts with the Sox in the majors at the end of the year. De Jesus Jr., who came to the Sox from the Dodgers in the August blockbuster deal, has hit for average and posted good OBPs in his minor league career (.298 average, .370 OBP), though his range is not equivalent to that of Martinez.

That’s not to suggest that a deal will be formulated between the Sox and Blue Jays involving a combination of the players mentioned. However, it does suggest that recent precedent is not in favor of the Sox parting with someone like Brentz — one of the Sox’ top power-hitting prospects with a chance to be an everyday outfielder in the big leagues by 2014 — or a player with a high probability of being a starting pitcher in exchange for a manager.

Of course, the Blue Jays will likely seek a more impactful package than Carpenter and Kurcz or Marinez and Martinez brought to their respective clubs — particularly given that Farrell would be moving to a division rival. For instance, if the Sox wanted to explore a young reliever construct for a deal, the Jays would likely ask (and almost immediately receive a vociferous “no”) about Junichi Tazawa. Or Toronto could target a player with a higher ceiling than a reliever about whom industry opinion is divided.

One such Red Sox prospect, in Double-A this year, was Drake Britton, a power lefty who had some terrific stretches in a breakthrough season as a starter in High-A Salem and Double-A Portland. Some scouts view him as a future power lefty out of the bullpen, others see the diversity of his repertoire (mid-90s fastball, slider, curve, change) and believe that, with time, he could improve upon his pitch inefficiency to become a starter. Britton will likely rank in the second half of Baseball America’s Red Sox top 10 this year.

Ranaudo, meanwhile, went through a year that was derailed by injury, in which his velocity and stuff suffered when he returned from a spring training groin injury, and in which he was shut down with a dead arm in the first week of July. He recently pitched in the fall instructional league, and while his stuff wasn’t back where it had been in spring training, it was superior to what it had been this year in Double-A Portland (where Ranaudo had a 6.69 ERA in nine starts). Last week, Ranaudo was throwing 92-93 mph with a power curveball.

At a time when the Sox’ system is deeper in potential starters than it has been in years, it would be interesting to see if the Sox would be willing to consider moving a potential starting pitcher or everyday position player. If the Sox do so, however, it would be a steeper price than either the Marlins or Cubs paid last year.