Offense kept Mariners afloat during first half of season

The Mariners reached the All-Star break with a 45-44 record. Here are first-half grades for the offense, defense, starting pitching and bullpen:

Offense: A-

For once it’s not a weakness. In previous years, strikeout-prone, all-or-nothing teams would go through extended dry spells with no production and no way to manufacture runs. This team hasn’t had that issue, averaging 4.89 runs per game, sixth-best in the American League. It’s the Mariners’ highest first-half average since 2007.

The Mariners rank seventh in the A.L. in batting average (.263), are tied for seventh in on-base percentage (.328), are third in slugging (.444) and second in home runs (132). Sure, they could be a little better with situational hitting, particularly with a runner on third and fewer than two outs: They have a .264 batting average (second-worst in the A.L.) and 41 strikeouts (most in the league) in that situation. The trio of Robinson Cano, Nelson Cruz and Kyle Seager have been outstanding. All three have on-base plus slugging percentages over .900 and have 66 doubles, 62 homers and 177 RBI total. Dae-Ho Lee, Seth Smith and Leonys Martin have provided better-than-expected production.

Defense: C

The grade might be lower if not for the exceptional play of Martin in center and catcher Chris Iannetta’s handling of the pitching staff. FanGraphs’ Defensive Runs Above Average metric has the Mariners at -21.2, which is 12th in the American League. Seattle has been charged with 58 errors — tied for third in the AL. They have had physical and mental mistakes and some unexpected errors from Seager at third base.

Though general manager Jerry Dipoto wanted a team that played a better style for Safeco Field, only Martin has really addressed that need. He has been brilliant despite playing with a hamstring issue since mid-June. When Martin was on the disabled list and Norichika Aoki was in center, the Mariners’ defense suffered in a big way. Shortstop Ketel Marte is among four players who are tied for the most errors in baseball with 13. Though he has made spectacular plays, he has had issues on some routine balls. But at age 22, some errors were expected.

The Mariners’ pitching staff also has been less than stellar at controlling the running game, not giving Iannetta a chance against would-be base stealers.

Starting pitching: D

You could give this group an incomplete considering the injury issues, particularly with absence of ace Felix Hernandez since June 1. Through May, the Mariners had used the five starters that broke spring training — Hernandez, Hisashi Iwakuma, Taijuan Walker, Wade Miley and Nathan Karns. Since then, James Paxton (eight starts), Wade LeBlanc (three), Mike Montgomery (one), Vidal Nuno (one) and Adrian Sampson (one) took turns in the rotation thanks to injuries. Only the Oakland A’s used more starting pitchers in the first half.

Since May 27, starting pitchers have posted 22 starts of five innings or less in 43 games. That stretch destroyed the bullpen. The Mariners have just 40 quality starts (six or more innings and three or fewer runs allowed) for the season. Iwakuma has been Seattle’s best starting pitcher, posting a 9-6 record and a 4.25 ERA. In his past 11 starts, he has had 10 with six innings or more, posting an 8-2 record in that span. Paxton and his new arm slot have given the Mariners some hope that he’ll fulfill his vast potential. Hernandez is scheduled to return July 20, and Walker (foot) is expected back a week after that.

Relief pitching: C

The low grade is a product of the bullpen being overworked for much of June when the starting pitching was abysmal. Seattle relievers struck out 315 batters, second in the AL, and posted a 3.44 ERA, which was fifth-lowest in the league. But the bullpen leads the AL with 16 blown saves and has served up 39 homers.

The patchwork group didn’t have high expectations coming into the season but pitched well in the first two months when used in proper roles. Then overuse and overexposure led to problems in June. It led to key right-hander Nick Vincent going on the disabled list. Setup man Joaquin Benoit was expected to fill a major role, but early shoulder issues followed by inconsistent command have limited his effectiveness.

Rookie Edwin Diaz, outstanding since being called up, looks to be a future closer. Montgomery’s versatility in the bullpen has been a plus, and the Mariners seem to have fixed a broken Tom Wilhelmsen.