Phoenix, AZ (SportsNetwork.com) - The Arizona Diamondbacks made their first offseason move towards bolstering their rotation on Friday, acquiring former American League Rookie of the Year Jeremy Hellickson from the Tampa Bay Rays in exchange for two minor league prospects.

The Diamondbacks sent infielder Andrew Velazquez and outfielder Justin Williams to Tampa Bay in the first trade orchestrated by new Arizona general manager Dave Stewart.

Hellickson was named the AL's top rookie after compiling a 13-10 record with a 2.95 earned run average in 29 starts for the Rays in 2011. The 27-year-old followed up with back-to-back seasons of double-digit wins, but struggled to a 1-5 record with a 4.52 ERA during an injury-plagued 2014 campaign.

The right-hander was limited to just 13 starts last season after undergoing surgery in January to remove loose bodies from his elbow.

Hellickson owns a career 40-36 record with a 3.78 ERA over 115 major league games, all but seven of which have been starts. He's due a salary increase in 2015 as a second-year arbitration-eligible player, which likely factored in the small-market and rebuilding Rays' decision to make the deal.

Stewart had made improving a rotation that was among the worst in baseball in 2014 a high priority this offseason. The Diamondbacks' 4.44 ERA from their starters was the second-worst mark in the National League and ranked 27th in the majors.

Velazquez and Williams were rated as the 12th and 14th-best prospects, respectively, in the Arizona system by MLB.com.

The 20-year-old Velazquez was named the 2014 Midwest League Prospect of the Year after hitting .290 with nine home runs, 56 RBI, 15 triples and 50 stolen bases at Low-A South Bend and reaching base safely in 74 consecutive games during the season.

Williams, 19, was the Diamondbacks' second-round pick in the 2013 draft. The left-handed hitter batted .351 with four homers, 46 RBI and five triples over 74 games between South Bend and Missoula of the Rookie-Advanced Pioneer League.