Trades and inefficiency have thinned the Red Sox farm system at the upper levels, leaving Boston’s depth in question.

But an opportunistic signing in the spring may help the Red Sox this week. Right-handed pitcher Hector Velazquez has a 2-1 record and 1.55 ERA in five starts with Pawtucket. His next start is supposed to be Thursday, but the PawSox list the starter for that game as TBA.

Velazquez has 20 strikeouts and five walks in 29 innings.

Boston will need a starter either Friday (if Drew Pomeranz remains out with triceps tightness) or Saturday (with Kyle Kendrick sent down after two horrific starts).

Velazquez, 28, spent seven years pitching in the Mexican League. After a breakout season in 2016 (120 strikeouts, 16 walks, 2.47 ERA), major league teams got interested.

He signed with Boston in February.

If Velazquez gets the call, he would be the third PawSox starter summoned after Kendrick (0-2, 12.96 ERA) and Brian Johnson (1-0, 7.20).

Henry Owens, often the starter called up last season, is scheduled to pitch for Pawtucket on Tuesday. He has a 2.27 ERA, but a WHIP of 1.39, which includes 21 walks in 312/3 innings.

Don’t wait for any bats coming up from Pawtucket soon. Looking at the Pawtucket Red Sox batting statistics, only three players are batting above .250 through Sunday:

n Infielder Jantzen Witte, 27, a 24th-round draft pick in 2013 (.288/.799 OPS).

n Utility player Ryan Court, 28, a minor league free agent who never played above Double-A until last year (.283/.853).

n Outfielder Rusney Castillo, 29, removed from the 40-man roster last June (.271/.702).

It’s unlikely that either Witte or Court get a call up – although both can play third base, a position of weakness for Boston. Witte played 93 games at third for Pawtucket last year (only four this year) with four errors. Court was Portland’s third baseman for 59 games last year (none this year), with two errors.

Castillo needs to put up Ted Williams-type numbers before Boston looks his way. If Castillo goes back on the 40-man roster, his $10.5-million salary will put Boston over the luxury tax threshold.

Other notables are first baseman Sam Travis, off to a slow start (.245/.692), struggling outfielder Bryce Brentz (.165/.506) and injured catcher Blake Swihart (.208/.625 in 13 games). Swihart is on the disabled list with a bruised finger.

Outfielder Aneury Tavarez, recently called up from Portland, has only played seven games (6 for 30).

IN PORTLAND, the talk always begins with third baseman Rafael Devers, who is batting .324/.984, with seven home runs and seven doubles. At third base, Devers has four errors in 29 games. If Devers keeps up the offensive numbers, he could be in Pawtucket in June to face more advanced pitching. … Reliever Jamie Callahan (1.38 ERA/0.62 WHIP) was promoted to Pawtucket.

Starter Travis Lakins replaced Callahan on the roster. He is scheduled to make his Double-A debut Wednesday at Hadlock Field against Hartford. Lakins, a sixth-round draft pick out of Ohio State in 2015, was 5-0, 2.61 in Salem. … Left-hander Jalen Beeks (5-1, 1.38) has thrown four straight scoreless outings, and hasn’t allowed a run in five of six starts this season. His 41 strikeouts and 16 walks in 322/3 innings should have him being considered for a bump up. Beeks has faced only two teams this year – Reading (four times) and Trenton (twice).

IN SALEM, third baseman Michael Chavis (.330/1.076, seven home runs) has kept his numbers up. … Jordan Weems, who once was a catcher/first baseman (on Portland’s roster early in 2016) continues his transition to reliever. He is 4-1 with a 2.63 ERA and 0.95 WHIP. … Right-handed sidearm reliever Trevor Kelly has a 0.64 ERA/0.93 WHIP with 12 strikeouts and four walks in 14 innings.

IN GREENVILLE, starter Shaun Anderson (3-0, 2.56, 37 strikeouts in 382/3 innings) was promoted to Salem. Anderson, 22, was a third-round draft pick last year out of the University of Florida. … Third baseman Bobby Dalbec’s promising start this season has faded to a .264/.716. Most troubling are the 44 strikeouts in 106 at-bats.

Kevin Thomas can be reached at 791-7411 or:

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Twitter: @ClearTheBases