3 surprise teams who could target Luis Castillo or Tyler Mahle in a trade

2. The Diamondbacks could be a surprise team to trade for Reds pitchers Luis Castillo or Tyler Mahle.

The Philadelphia Phillies were thought to be contender in the National League this season, but I don't think many people felt as though the Arizona Diamondbacks would be that same conversation. But here we are in the middle of May and the D-Backs have a better record than the Phillies.

Not only that, but the D-Backs have one of the best starting rotations in all of Major League Baseball. Only the highly-touted Los Angeles Dodgers starting rotation has a better ERA. But that doesn't mean that Arizona shouldn't look to improve their rotation.

After all, the D-Backs reside in the incredibly difficult National League West. Every team in that division currently has a winning record. That won't be the case for long, especially if the Diamondbacks don't bolster their rotation.

Madison Bumgarner, Merrill Kelly, and Zac Gallen have gotten off to extremely good starts, but the same cannot be said for Humberto Castellanos. The D-Backs also have Zach Davies in the rotation, and while serviceable, the former Milwaukee Brewers starter isn't going to win a Cy Young Award anytime soon.

Adding Luis Castillo or Tyler Mahle to the Arizona Diamondbacks rotation could be an extremely shrewd pickup on the part of general manager Mike Hazen. Having one of the Cincinnati Reds starters join the likes of Bumgarner, Kelly, and Gallen for the next year-plus could really elevate the D-Backs chances of competing in the NL West this season and beyond.