SEATTLE -- J.P. Howell continues to make progress from the "weak" left shoulder that sidelined him during Spring Training and has kept him out of action while he rebuilds the strength in the shoulder.

Rays manager Joe Maddon expects the left-hander to throw a couple more "side pieces" in advance of a simulated game. Howell has thrown breaking pitches, and throwing back-to-back side sessions is next on his ladder of progression.

Maddon would not commit to a date when Howell will return. The pitcher has said he would be back at the end of May.

"It's going to be close," Maddon said. "He's on task right now. He's doing well. Barring any setbacks, it's pretty much the end of the month, beginning of next month right now."

Pena closing in on Rays' walk record

SEATTLE -- Carlos Pena enters Thursday's game with the Mariners needing two walks to tie Fred McGriff for the all-time club mark.

Pena has 303 walks, while McGriff drew 305 during his Rays career from 1998-2001 and in '04.

Pena, who tied for the American League lead in home runs in '09, values his walks.

"If I'm walking, I'm hitting," Pena said. "[Rays manager] Joe [Maddon] says that, and I'm agreeing with him 100 percent of the time. And if you think about it, a walk is just as good as a hit. You're on first. You heard that, right? That's a very popular line. It's true. ... You're on first base, and you're helping your team out."

While Pena values his walks, he said a hitter can't go up to the plate trying to draw a base on balls.

"I've seen times where I'll have walks and I'm happy I'm on first base, but I know that earlier in that count, I missed two pitches I could have hit for a double, maybe a home run, or I've just flat taken a pitch down the middle," he said. "So I know you cannot go up to the plate trying to walk, or trying to work counts."

Pena described his "perfect world" scenario for getting a walk.

"You have a plan," Pena said. "You're waiting for a good pitch to hit. You don't get it, you go to first. That's the way I like to get them."

While Pena likes to walk, he wouldn't go so far as to say that drawing a walk was more satisfying than hitting a home run.

"But sometimes I'll get a walk and I'll be like, 'That's an outstanding job, good job,'" Pena said. "And I go to first base and I'm like, 'Great job, I feel happy about what I just accomplished. The guy was throwing some tough pitches and I laid off them.' Maybe I watched him on video and I kind of knew, so there is some pride to be taken there, but it definitely feels better to crush a baseball."

Only three other Major Leaguers besides Pena have 300 or more walks since the start of 2007: Adam Dunn, Albert Pujols and Jack Cust.

Rays braving the cold road

SEATTLE -- In the Rays' first 11 road games -- at Baltimore, Boston, Chicago and now Seattle -- the average game-time temperature has been 49 degrees, ranging from a low in Boston and Chicago of 39 to a high of 66 in Baltimore.

Rays players have gotten used to dealing with the cold, which can be particularly tough on players like Carl Crawford who like to run a lot.

Crawford talked about his approach when the team is playing in cold weather.

"I just come early and run -- get used to the weather outside," Crawford said. "[I] try to stay warm any way I can -- get in the hot water. They've got heaters around here."

Crawford said that once he gets loose, he stays loose.

"Once I feel loose, I stay nice and loose, I'm not stiff," Crawford said. "I mean, you get cold when you're standing out there. But you've got the guys [on the Rays' staff] pitching pretty good, and we're not standing out there too long. Fortunately for us, we haven't had any real long innings in the cold yet."

Extra bases

Rays reliever Grant Balfour is friends with the Mariners' scheduled starter for Thursday night, Ryan Rowland-Smith, who is also from Australia. When asked about his friend, Balfour noted: "He's a pretty good surfer." ... James Shields' 10-strikeout, no-walk performance Tuesday night was the 10th time a Rays pitcher has turned the trick; Shields has now done it three times. ... Despite going 3-for-25 with runners in scoring position the past four games, the Rays still lead the Major Leagues with a .315 batting average in those situations (76-for-241).