Erik Bedard has been frustrating. There’s no other way to put it.

He was the Pirates’ Opening Day starter, and held true to that title through the month of April. In one span, he made hitters swing and miss so much that their whiffs created a tornado.

But now his season numbers in ERA and WHIP are now worse than Kevin Correia. What happened to the dominant Bedard we saw in April? Where is the pitcher that everyone said would be good as long as he stays off the disabled list?

Before we explore that, let’s look at his repertoire. Bedard is largely a three-pitch guy: four-seam fastballs, two-seam sinkers and curveballs have made up 85 percent of his pitches this year. He will also occasionally mix in a changeup to righties and a new cutter to lefties.

With that in mind, here are the five main factors for Bedard’s struggles, as I can tell. As always the data is from the indispensable Brooks Baseball.

1. His velocity is down.

This is not a huge surprise, since Bedard is now 33 years old and has been more banged up than Eric Lindros. But even from last year to this year, the average velocity on Bedard’s fastball has dropped from from 91.2 mph to 89.6 mph.

This leads to one major problem: the other team is hitting his fastball harder. Last year, 16.5 percent of Bedard’s four-seam fastballs put into play were line drives. This year, 26 percent of his fastballs put into play have been liners. It’s a small sample size, with only 46 fastballs being made playable this season, but 16.5% to 26% represents a huge jump.

The drop in fastball speed is likely making his changeup less effective as well. If your fastball is not a high-speed threat, that changeup becomes more hittable.

2. Bedard is not generating swinging strikes, especially since his minor injury in May.

A huge part of Erik Bedard’s game is getting opposing hitters to whiff. Between 2007 and 2009, he was one of the best pitchers in the American League at getting hitters to swing and miss. That ability has steadily decreased since that time.

He is not getting as many swings and misses on his fastballs and changeups, which hurts his overall game. Before Bedard suffered back spasms on May 9, he was getting opposing hitters to whiff on 9.2 percent of his pitches. Since then, only 6.9 percent of his offerings have made hitters swing and miss. That leads to a lower strikeout rate and a higher walk rate.

The back spasms are far from the only reason for Erik Bedard’s struggles. But you can’t deny that the injury has represented a pivot point for his results this year.

3. Righties are hitting him better than they ever have before.

For most of his time in the Majors, Bedard has been known as a left-hander without a discernible platoon split: righties have a .693 OPS against him over his career and lefties have a .681 OPS. Not much to see there.

This year has been different. Right-handed hitters own a .791 OPS (and 8 homers) against Bedard this season, compared to lefties hitting for a .656 OPS. Again, small sample size since Bedard has only faced left-handed hitters in 78 plate appearances.

But compared to 2011, Bedard is striking out far fewer righties and walking far more of them. That is beyond problematic; it is part and parcel to his troubles. He needs to work on his fastball command. Against righties this season, he is not throwing his four-seamer for strikes as often (38.4 percent ball rate vs. 35% ball rate last year).

4. His sinker has not been as effective.

It is a small qualm, but Bedard has not gotten great results from his two-seam sinker. The sinker is a big part of Bedard’s repertoire, especially against left-handed hitters.

The problem is that sinker has lost velocity just like the four-seamer, and it is not getting hitters to swing and miss. Instead, they are hitting it harder than ever:

The ground-ball rate is encouraging. But the fact that hitters are getting so many line drives off Bedard’s four-seam and two-seam fastballs (again, loss of velocity) means that Bedard has the 6th-highest line-drive rate among any National League pitcher. If hitters are knocking line drives off you, you are in trouble.

5. He needs to improve his pitching from the stretch.

For some reason, Bedard has a 2.8 strikeout-to-walk ratio with the bases empty this season, but a 1.3 strikeout-to-walk ratio with men on base. There’s nothing in his career before Pittsburgh to demonstrate any innate trouble with pitching from the stretch, so perhaps Bedard just needs more confidence attacking the zone with runners on.

So what’s the solution?

I’m not a pitching coach. But Ray Searage is, and he is a very good one. He has overseen the breakthroughs of Jeff Karstens and James McDonald, and the potential renaissance of A.J. Burnett and Brad Lincoln. I can only speak to what I have seen in Bedard’s starts and what the data tell me.

— Don’t let Bedard start until July 20. That will give Bedard 13 days between Major League starts. That is one week to rest and one week to work on his command. When he returns on the 20th, that would give Bedard three starts before the MLB trade deadline. If the rest does Bedard and his back some good, he can earn his rotation spot for August. If he continues his downturn, there will be other pitchers available to take his spot.

(Note: It looks like manager Clint Hurdle will give Bedard 10 days of rest between starts to “give him time to tweak,” per Kristy Robinson. That sounds pretty good.)

—  Have him throw more curveballs (especially for first pitch). Bedard seems to work off his fastball and changeup for his first pitch. But Bedard’s curveball is probably his one true “plus” pitch, and he can command it for strikes a decent two-thirds of the time. At this point of his struggles, everything is up for debate, even the pitches that Bedard works off to start at-bats.

— Work on fastball command. If the velocity is down on Bedard’s fastball, so be it. Aging is a bitch. But Bedard is walking 10 percent of hitters this year, which is among the highest rates in the NL. On Friday night, Bedard walked Buster Posey on four straight fastballs. That’s unacceptable. If he can’t consistently put his fourseam fastball in the zone, Erik Bedard won’t be long for this baseball world. Use Bedard’s period between starts to work on getting that fastball on top of the plate.

But look back before that four-pitch walk to Posey on Friday night. The first time through the Giants order, Bedard through three no-hit innings with only one walk. That’s what he can do: generate flyballs and groundballs and get hitters to whiff and give the Pirates a chance to win.

To go back to the old sabermetric standby, Erik Bedard’s second-half ERA will probably be closer to 4.19 (his current xFIP) than his first-half 4.80 ERA. That is a decent jump, but it won’t happen just because the numbers say they should. Bedard has a lot to work on.

The Pirates have already received enough good starts from Bedard to make him worth the one-year, $4.5 million contract. But if he can look more like the pitcher fans saw in Baltimore and Seattle, he could be worth so much more. He could even be on the PNC Park mound as the Bucs wrap up a pennant.