As the weeks click by in Red Sox spring training, it's become increasingly apparent that Kyle Kendrick should be Boston's top choice among depth starters.

The 32-year-old Kendrick has allowed just three runs over 18 innings in five games, four starts.

But while Kendrick's strong impression has put him at the top of the leaderboard, fellow newcomer Hector Velazquez remains a question mark.

On Sunday, Velazquez tossed two innings, allowing four runs on four hits and a walk while striking out two in Boston's 13-8 loss.

Since arriving in Red Sox camp in late February as a relative unknown, the right-hander has made four appearances, including two starts. He's given up a total of 11 runs over nine innings. And yet still remains a relative unknown.

Part of the problem the Red Sox encountered after acquiring Velazquez from the Mexican League in mid-February was managing his significant workload from the previous season.

Velazquez tossed 131 innings over 22 starts in the regular season for his Mexican League club followed by an additional 115 1/3 innings in the Mexican Pacific Winter League (85 1/3 innings) and the Caribbean Series (30 innings).

That amounts to a whopping 246 1/3 innings in 46 starts over the last 12 months. The Red Sox were intrigued with his consistency as he put up a 2.37 ERA with 242 strikeouts and 39 walks, but they've had to pump the brakes on evaluating him fully this spring given his absence of a true offseason for the righty.

The Red Sox plan to keep Velazquez to three-inning stints or shorter before stretching him out. It's possible he even remains in extended spring training to prolong his rest period before joining a minor-league rotation, likely in Triple-A Pawtucket.

"More than anything, we're just trying to protect it a little bit and slow him down so that he rejuvenates and stays fresh," manager John Farrell said recently.

The pursuit of Velazquez began last fall when Red Sox president of baseball operations Dave Dombrowski called for a greater scouting emphasis on the Mexican League.

The duties fell to vice president of player personnel Jared Banner and his team, who scoured their contacts in Mexico and mined statistical data to identify Mexican League players they should target.

Over the course of the winter, the 28-year-old Velazquez popped onto their radar. He was coming off a breakout season with a 2.47 ERA, 120 strikeouts and just 16 walks in 131 innings in 22 regular season starts.

Velazquez continued his dominance over 14 starts in the Mexican Pacific Winter League with a 2.32 ERA, 87 strikeouts and 16 walks in 85 1/3 innings and then dominated in the Caribbean Series with a 2.10 ERA, 35 strikeouts and seven walks in 30 innings over five starts.

The Red Sox had video and saw his numbers, but it wasn't until the Caribbean Series in February that scouts were able to get an eye on him.

He quickly wowed player personnel assistant Marcus Cuellar and Puerto Rican player personnel crosschecker Edgar Perez, but there wasn't much time as other teams, including the New York Yankees, were eyeing him as well.

"(They) saw what they were looking for in the first outing," senior vice president of player personnel Allard Baird said. "Said we'll see him again, but that really rang the bell to start the work on the makeup of the player on the field, off the field, his history."

What exactly were they looking for?

"No . 1 you looked at him as an athlete and his adjustability, even though he's 28 years old, he was a former position player, his game and field awareness, how he handled in pressure situations, believing that was going to be transferrable over here, how he held runners, his times to the plate, how his fielding would be, those little things make it easier," Baird explained. "Then besides that, he's not a guy that's going to out-stuff anybody, it's going to be a lot of contact outs, so believing he was going to have the ability to control and command his pitches gave us confidence with our professional instruction that we saw some value, bring him in our organization and we'll see how it all works out."

Mexico lost to Puerto Rico 1-0 in extra innings of the championship game of the Caribbean Series on Feb. 7. By Feb. 18, the Red Sox had signed Velazquez and he was in camp the following week.

The intrigue with Velazquez, who throws a fastball, changeup, splitter and cutter, is that no one knows much about him.

That's why the Red Sox wanted to throw him into the mix this spring to see how he could handle major-league competition for the first time.

However, they realized they weren't necessarily seeing his best stuff on a less-than-fresh arm.

So extra days were built into his schedule to keep him loose but rested.

"The bottom line is he's going to be a guy that has to command his pitches, not just control them but command them, and utilize his secondary stuff probably backwards at some point," Baird said. "We like how he's handled himself and time will tell. We're glad we signed him and we'll see where it goes."

If the Red Sox need starting help early in the season, Kendrick will likely get the call. But Velazquez could play a crucial role later in the season once he's settled in.

Follow MassLive.com Red Sox beat reporter @jcmccaffrey on Twitter. She can be reached by email at jmccaffr@masslive.com.