Rich Cimini does a good job laying out reasons the San Francisco 49ers might consider trading for New York Jets cornerback Darrelle Revis.

I'll give you five reasons to think twice.

Philosophy test: Smart NFL teams know drafting well beats signing veterans from other teams to inflated deals. Drafted labor is cheaper, healthier labor. After spending big in free agency to prop up a shaky roster five-plus years ago, the 49ers have taken a disciplined approach to improving the team. Revis will want a massive contract extension. If the 49ers weren't interested in signing Nnamdi Asomugha as a free agent a couple years ago, why would they suddenly part with draft compensation for the right to pay another veteran corner? It's not the 49ers' way.

Chemistry concerns: The 49ers have taken care of their own players. They've reached contract extensions with Joe Staley, Vernon Davis, Patrick Willis, NaVorro Bowman and other players they drafted. The approach has sent a strong message through the 49ers' locker room. Produce and the team will value you more than it values players from other teams. Spending big for a veteran from another team would go against form. Revis might be good enough to warrant an exception from the 49ers' standpoint, but that is not a given.

Misplaced need: The 49ers' secondary struggled late in the season, no question. Facing red-hot quarterbacks such as Tom Brady, Russell Wilson, Aaron Rodgers and Matt Ryan had something to do with that. Also, the 49ers' pass rush wasn't as good when injuries struck Justin Smith and Aldon Smith. Bolstering the defensive line and improving the pass rush should be a higher priority than loading up at corner, particularly at an inflated price.

Revis is injured: Revis suffered a torn ACL last season. Will he recover the way Adrian Peterson recovered, returning to form quickly? Will he struggle? Might he never be quite as dominant as he was previously? The 49ers cannot know the answer to these questions. Their medical people don't know Revis the way their medical people know current 49ers players. Giving up draft compensation for the right to overpay a veteran is risky enough. It's even riskier when that veteran is coming off major surgery.